Research Component Report.docx

Research Component Report on

“Synthesis and Evaluation of Biocompatibility of Cu-Al-Mn Shape Memory Alloy.”

Submitted to

SIDDAGANGA INSTITUTE TECHNOLOGY, TUMAKURU In the partial fulfilment of the requirement for the award of BACHELOR OF ENGINEERING IN MECHANICAL ENGINEERING

Submitted by

ARUNABHA MAJUMDER USN: 1SI15ME027 Carried out at

SIDDAGANGA INSTITUTE TECHNOLOGY TUMAKURU-572103

Under the Guidance of Dr. Shivasiddaramaiah A G, M.E., Ph.D. Assistant Professor Department of Mechanical Engineering SIT, Tumakuru-572103

DEPARTMENT OF MECHANICAL ENGINEERING SIDDAGANGA INSTITUTE TECHNOLOGY (An Autonomous institution Affiliated to Visvesvaraya Technological University Belagavi, Approved by AICTE, Programmes Accredited by NBA, New Delhi & ISO 9001:2008 Certified) Tumakuru-572103, Karnataka India 2018-2019

Sree Siddaganga Education Society (R)

SIDDAGANGA INSTITUTE OF TECHNOLOGY (An Autonomous institution Affiliated to Visvesvaraya Technological University-Belagavi,

Approved by AICTE, Programmes Accredited by NBA, New Delhi & ISO 9001:2008 Certified)

Tumakuru-572103, Karnataka India (10)

Department of Mechanical Engineering

CERTIFICATE This is to certify that the Research Component Report entitled “Synthesis and Evaluation of Biocompatibility of Cu-Al-Mn Shape Memory Alloy.” is prepared and presented by Arunabha Majumder (1SI15ME027), in partial fulfilment of the requirements for the fourth year of Bachelor of Engineering in Mechanical Engineering at Siddaganga Institute of Technology-Tumakuru, during the academic year 2018-19. The report has been approved as it satisfies the academic requirements for the Bachelor of Engineering Degree.

Guide:……………………………….. Dr. Shivasiddaramaiah A G, M.Tech., Ph.D. Assistant Professor Department of Mechanical Engineering SIT, Tumakuru

HOD:…………………………….. Dr. K.S. ShashiShekhar, M.Tech., Ph.D. Professor and Head Department of Mechanical Engineering SIT, Tumakuru

Principal:………………………… Dr. K.P. Shivananda, M.E., Ph.D. Principal Siddaganga Institute of Technology, Tumakuru

External Examiner Name of the Examiner 1. 2.

Signature ……………………………. ...…………………………..

DECLARATION I hereby declare that the research component work entiled “Synthesis and Evaluation of Biocompatibility of Cu-Al-Mn Shape Memory Alloy” is an authentic work that has been carried out at SIDDAGANGA INSTITUTE TECHNOLOGY, TUMAKURU, Under the Guidance of Dr. Shivasiddaramaiah A G, Assistant Professor, Department of Mechanical Engineering, SIT, Tumakuru as a part of my study award of degree of BACHELOR OF ENGINEERING in MECHANICAL ENGINEERING of Visvesvaraya Technological Institute, Belgavi, Karnataka. The work contained in the report has not been submitted in part or full to other university or institution or professional body for the award of any degree/diploma or any other fellowship.

Date:

Signature of Student

Place:

(ARUNABHA MAJUMDER)

ACKNOWLEDGEMENT No research or venture is complete without the assistance and guidance by many people who constantly help me in reaching the final point. The commendation of the successful completion of the work is to those hands which stood by me in every small step we took. I am using this opportunity to express my gratitude to everyone who supported me throughout the course of this research. I am thankful for their inspiring guidance, invaluably constructive criticism and friendly advice during the research work. I am sincerely grateful to them for sharing their truthful and illuminating views on a number of issues related to the work. First and foremost, I would like to extend our sincere gratitude to Dr. Sree Sree Shivakumara Swamiji who is the forerunner of the Siddaganga Society. Everything would have been impossible without his omnipresent blessings bestowed on us. I also thank our beloved Director Dr.M.N.Channabasappa and the Principal Dr. Shivakumaraiah who are the founding stones in every endeavour. They are our constant benefactors who stood by us at all obstacles we faced. This Research would not have been realized without the consistent encouragement of Dr.K.S.Shashishekhar, Professor and Head, Department of Mechanical Engineering, SIT, Tumakuru. He was always a pillar of support who was never exhausted to assist me at any time. I take this opportunity to thank my guide Dr. Shivasiddaramaiah A G, Assistant Professor, Department of Mechanical Engineering, SIT, Tumakuru, for his support, invaluable advice and guidance which helped me to complete this research. Last but definitely not the least, the non-teaching staff who stood by me, helping me with the non-technical requirements. It would have been a nightmare without their love and cooperation. Above all, I would like to express thanks to my parents for their support all along.

ARUNABHA MAJUMDER

Abstract Shape Memory Alloys are the type of alloys which is capable of “remembering” its original shape. These alloys go through martensitic phase transformation when a thermo-mechanical load is applied to them and redeems their permanent strains when heated above austenitic temperature. These alloys have drawn the attention of various researcher and enthusiasts who are in the field of medical and commercial improvements because of their unique properties. The contemporary work represents the prime objective where a ternary shape memory alloy with an erratic weight percentage of 9-14 weight% Al, 5-9 wt. % Mn and remaining will be copper were synthesized and concluded for biocompatibility. The alloys were synthesized by blending them together through ingot metallurgy under a constrained atmosphere. These samples went through homogenisation at 900°c for 90 minutes, hot rolled to reduce the thickness, followed by Betatization at the same temperature for 30 minutes. Finally, they were step quenched in hot water (100°c) and then quenched in water at room temperature. The dimensions of 10mm*10mm*1mm (length*breadth*thickness) were achieved through machining processes. The shape memory effect was perceived in them during the bend test and then examined for antibacterial activity using turbido-metric technique. Staphylococcus aureus and Escherichia coli were the organisms used during the test and the results displayed a remarkable biocompatibility with the intention that it can be developed for in-vitro uses.

Chapter 1 Introduction 1.1

overview

The rapid Advancements of technologies in the field of aerospace, industrial and medical, there is a necessity to develop modern materials which will suit well for the applications specified. With the innovations of technologies of modern era, the expectation and the requirements are also growing. Smart materials are the promising answers for these increasing hassles of the modern technologies. Smart materials are the intelligent materials that respond to any stimuli or changes in the surrounding. It is almost similar to a living organism’s respond to stimuli or any environmental changes. These materials can feel/ sense, process and actuate a response. These materials can be used either separately or within an embedded system. Types of Smart materials are as follows: 

Piezo electric materials



Electrostrictive materials



Magnetotrictive materials



Shape memory Alloys



PH Sensitive materials



Smart gels



Magnetorehological materials



Electrorehological materials



Electrochromic materials.

In the field of research, Shape Memory Alloys are quite fascinating as they unveil two functional properties namely, Shape memory effect and pseudoelasticity. SMAs consist of smart metallic system that redeems its original shape or size due to the application of thermal as well as mechanical treatments. SMAs are classified based on combinations of alloys used. They are grouped into: Ni-Ti based SMAs and Copper based SMAs. Ni-Ti based SMAs are widely employed in the field of commercial applications as they show excellent shape memory effect, resistance to corrosion and shows great biocompatibility. In recent years Cu-based SMAs, for example, Cu-Al-Zn, Cu-Al-Mn, and Cu-Al-Be-Mn are broadly used in various fields such as marine, defence, aerospace, nuclear power plants and biomedical applications.

Cu based SMAs cost less, easy to manufacture, process and characterize as compared to NI-Ti based SMAs. They also demonstrate a good damping effect, sound absorption capacity and mechanical vibrations as a result of their grain size, high strength, and corrosion resistance. With these characteristics, it can also be applied in petroleum industries for pipe welding, joining pipes etc .

1.2

Definition Of Shape Memory Alloys

The alloys that exhibit the ability to redeem its predefined shape when laid open to an appropriate thermal or stress cycle are known as shape memory alloys. They are also termed as thermo-responsive alloys as they respond to the temperature change in the environment. They possess the ability to reminisce their unique shape even after permanent deformation and reverts back to its original shape when subjected to appropriate thermal or stress process. Once deformed at low temperature they maintains the new shape until they are heated. Shape memory Alloys are the smart metallic materials that have the remarkable ability to change their crystallographic arrangement from one form to other with the change in thermal or stress cycle. This change in the crystallographic structure helps them to maintain a precise shape at certain temperature range or level of stress and diverse shape at different temperature range or stress level. The two crystallographic Structure are known as Martensite which can observed at low temperature stage and Austenite at high temperature stage. The changes that occur in crystallographic structures leads to the transformation of solid phase from Austenite phase to Martensite phase and vice versa. The high temperature Austenitic Phase is also referred to as β or parent phase of the alloy.

1.3 Principle of working or unique properties exhibited by Shape Memory Alloy. The Shape Memory Alloy has two distinct properties due to the transformation of solid state from Austenitic state to Martensitic state. They are: 

Shape Memory Effect



Super Elasticity Pseudo Elasticity

1.3.1 Shape Memory Effect Shape memory effect is an inimitable property of Shape memory alloy when it is subjected to deformation at low temperature produces permanent strain which is recovered when heated at high temperature. After heating these alloys redeems its original shape which was observed before deformation. The crystallographic processes are shown in the Fig.1.

Fig.1. Mechanism of Shape memory Effect The main Principle behind this property exhibited by the Shape Memory Alloy is that at high temperatures the SMAs are in Austenitic Phase and when cooled, they transforms to Martensitic phase. During this transformation there is no macroscopic Change in the shape as twin Martensite occupies the same space as that was occupied by Austenite. Therefore the Martensite formed is known as Self Accommodating Martensite. The Alloy can be deformed in this phase and by application of stress which leads to deformed Martensite. This alloy on heating at an elevated temperature i.e. above its austenitic ending temperature, transmutes back to austenitic phase. During the change the strain will be removed completely there by recovering its original shape. It is known as Shape Memory Effect.

1.3.1.1. One-Way SME

SME or one-way shape memory effect is the unique ability of SMAs due to which they recuperates their original Shape when they (in deformed shape) are heated above austenitic ending temperature. Figure.2 shows a diagram in which the SMA spring is bent in an interminable supply of load. Under the load, after warming the SMA spring above Austenitic ending Temperature, the spring reverts back to its original unreformed state. Exactly when twinned martensite is loaded, it reorients and in this way, additional varieties of martensite start confining to the weakness of less perfect varieties. The alloy thru unloading when heated above Austenitic ending temperature clenches the de-twinned shape and invert change occurs. The alloy Changes to martensite, when the spring is cooled as shown below.

Fig.2. One-way shape memory effect

Fig.3. shape memory effect

1.3.1.2. Two-Way SME

In one– way memory effect there is only a solitary shape recalled by the alloy i.e. the parent stage shape (assumed searing shape). These alloys can recall both hot state and cold state shapes by cycling them between two unique shapes without the necessity for outside load. Two– way shape memory effects depend totally on changes in microstructure and martensitic stage which happens influenced by inward pressure. Self– settlement of the martensite microstructure is lost in the two– way effect on account of the nearness of these internal pressure. Overwhelming varieties are formed amid change. These results in achieving distorted martensite stage particularly by cooling parent stage influenced by inner pressure. Inner pressure may be displayed in different ways. Generally, we examine 'preparation' of shape memory alloy. Internal pressure must be unfaltering on warm-pressure through the change. Inward pressure is ordinarily a delayed consequence of irreversible defects. After each loading– purging cycle, a little leftover strain remains. Irreversible defects can moreover be made through the presence of particles. Two of the most generally perceived getting ready systems make two– way memory through the introduction of dislocation arrays and are refined by: • Cyclic distortion at a temperature underneath Mf took after by obliged warming presented to the unforgiving components shape to a temperature beyond Austenitic finish. • Cyclic distortion between the hot and cold– shapes at a temperature beyond Austenitic finish.

Fig.4.Two-way shape memory effect

1.3.2. Super Elasticity Pseudo Elasticity

One of the properties that makes SMA a brilliant materials is the super elasticity. It is a phenomenon due to which a deformed SMA due to large strain induced in it are recuperated upon unloading. When a SMA above its austenitic temperature is subjected to loading leads to the formation of rescindable stress induced martensite. As the load is removed the SMA transforms back to its original shape as it was already present in its austenite phase. In this case the martensitic phase is present at very low temperature (in some cases below room temperature). This property leads to a very high elasticity known as super elasticity.

Fig.5. Characteristic plot of stress-strain curve showing super elastic effect

1.4 Biocompatibility The association of living organisms with a completed medical device or a segmented material is termed as biocompatibility. A typical definition is” the nature of being impeccable with the living organisms but not being detrimental or causing any dismissal to immunological system”. It is an important factor for the medical contrivances and thus it is evaluated for both local and systematic responses. The last type of the thing is subjected to all of testing. The test outcomes may be affected by the living organisms or impurities present, so test articles are disembowelled and also sterilized with an undefined strategy from foreseen creation. In any case, sterility isn't exactly the equivalent as biocompatibility. The nonattendance living beings, (for instance, tiny life forms) from a material's surface is defined as sterility.

Consequently, all the implantable materials ought to experience following imperative tests previously going for human implantation: 1. In-vitro test (Cell culture test) - In vitro-utilization of tissue culture/microscopic organisms on Petri dish. 2. In-vitro test (Implantation test) - Animals are utilized for testing biomaterials to demonstrate the condition that may be experienced in people. Shape Memory Alloys are extensively used in numerous medical applications such as orthopaedic applications i.e. femoral shaft fracture and several expatriated femoral neck of the leg, dental implants, and stents reducing the likelihoods of heart attacks.

a

b Fig.6. In-vitro test: (a) Cell culture test, (b) Implantation test.

1.4.1 In-vitro Antibacterial Tests The two strains of bacteria were selected for In-Vitro test and they are 1. Staphylococcus aureus 2. Escherichia coli.

Staphylococcus aureus: S. Aureus is a gram-positive bacteria which is round in shape and can be found in marine species as well as human respiratory system. This bacteria gives positive result with decrease rate of nitrates. This bacteria is capable of surviving without oxygen. This microscopic organisms cause contaminations by extricating factors, for example, poisons on the surface of the cell which thusly covers and inactivates the remote substance present.

Fig.7. Image of Staphylococcus aureus bacteria

Escherichia coli: Escherichia Coli is a gram-negative microscopic organisms as round and hollow bar shape which exists inside the small intestine of warm-blooded living beings. The vast majority of these microscopic organisms are innocuous aside from not many which causes sustenance harming. The infinitesimal creatures which are said to be shielded comforts for host organisms by charming vitamin K and moreover confines the advancement of dangerous microorganisms inside the stomach related tract. E.coli performs like a visitant and aides in doing substantial

amount of DNA cell works.

Fig.8. Image of Escherichia coli bacteria

1.5 Bio-Medical Applications There are numerous applications of SMAs in clamping of fracture bones and to tie surgical stitches on human body. Shape Memory Alloys are extensively used in numerous medical applications such as orthopaedic applications i.e. femoral shaft fracture and several expatriated femoral neck of the leg, dental implants, and stents reducing the likelihoods of heart attacks. Stainless steel stents because of their great flexible properties were utilized as catheter to the artery wall in prior days. Be that as it may, now, because of self-expanding property shape memory compounds are utilized in cardiovascular applications. SMAs will change in accordance with the body temperature because of its great shape memory property. Consequently, SMA Stents are favoured as opposed to customary materials. Braces are used for remodelling of bones. Due to the increase in development of SMAs, they are also used orthodontic braces. The braces made out of Ni-Ti alloy are used in most cases as they have improved tolerance, reduced length and also easy to replace.

a

b Fig.9. Applications: (a) Dental Implants (b) Mechanism of stent.

Chapter 2 Literature Survey Gupta et al in the year 2012 studied the working principal of the transformation of SMAs, Commonly used alloys and their applications. Shape Memory Alloys are the type of alloys which is capable of “remembering” its original shape. These alloys go through martensitic phase transformation when a thermo-mechanical load is applied to them and redeems their permanent strains when heated above austenitic temperature. Although having all these advantages, SMAs have disadvantages too and are need to be overcome. They have poor fatigue strength and expensive to manufacture. Researches are going on to overcome these disadvantages and to find new applications of SMAs [1] Fatiha El Feninat et al in the year 2002 have studied for the biomedical applications of SMAs. The biocompatibility of these alloy for a long duration has not been achieved. The mechanical properties of these materials have been used for various biomedical applications. These materials are widely used for the making body implants. Since SMAs might have adverse effects on living cells if used for a long duration, in that case Shape Memory polymers seems to be a promising material. SMAs have their potential in the field of medicine though shape memory earthenware production potential bio-therapeutic applications are as yet unexplored. [2] Hironari Taniguchi et al in the year 2013 have learned about Flexible pseudo muscle actuator utilizing curled shape memory alloy wires. The actuator utilized comprises of SMA wires and adaptable materials. The manufacture which is done here depends on the moulding of silicon elastic. By the movement with the body in flexion describes the actuator. A few qualities were estimated to explore the connection between the activation and the bending angel of its body. Therefore incitation with the body in flexion was conceivable. Here, an adaptable counterfeit muscle actuator utilizing SMA wires which are coiled are proposed. The guide instance of the actuator is created utilizing silicon elastic and incitation and power execution was examined. From the exploratory outcomes, the movement of the actuator was affirmed when the focal point of its actuator was bend 0 to 90 degrees. With the expansion in bending angel displaced and forced both diminished progressively. The principle purpose behind this was observed to be shape twisting of its guide case [3].

Kenneth Kanayo Alaneme et al in the year 2016 have studied about Cu and Fe base SMAs. SMAs exhibit anthropomorphic features. This alloys is a possible substitute for NI-Ti base shape memory alloys in terms of cost. The paper work consists of various studies based on the properties of Shape Memory alloys which is applicable to Cu and Fe based alloys. The Cubased compounds applications are impeded because of their grain boundary break, natural fragility, and maturing and poor fatigue life. This confines material life, formability and the shape memory limit of the framework. A portion of these restrictions are diminished by utilizing melt turning and hot densification rolling [4]. Aksu Canbay et al in the year 2017 have found out about Cu-Al-Mn SMA having diverse sytheses was set up by using melt techique to control the stage change parameters. The fundamental properties and stage change parameters of the alloys were analyzed by optic microscopy, differential Scanning calorimeter. The effects of the alloy on enthalpy, entropy estimations of Cu-Al-Mn ternary systems were investigated, trademark transition temperatures. The affirmation of the effect of aluminum and manganese composition on the transition temperature is done to find ordinary crystallite measure for the alloys.[5] Raju G. Kammula et.al has learned about biocompatibility assessment of the medical gadgets. By and large, evaluating the biocompatibility of medical gadgets and biomaterials has been a mind boggling task. This multifaceted nature rises up out of how gadgets are made of a contrasting extent of materials and have diverse proposed uses, with body contact going from transient skin contact to contact with blood to immutable implantation. There are a couple of national and universal accord standards that address the toxicological evaluation of therapeutic gadgets. As of late, the Center for Devices and Radiological Health (CDRH) — has been pondering the use of these understanding benchmarks to help the biocompatibility review of therapeutic gadgets. This article looks at the data required by FDA to evaluate remedial gadgets already clearing or embracing them for the market, or supporting their examination in human subjects. It is like manner portrays how FDA starting at now, uses perceived agreement measures to energize the biocompatibility review of helpful gadgets [6].

Objective 

To prepare the ternary Cu-Al-Mn alloy with different chemical composition through ingot Metallurgy.



To determine the percentage shape memory effect, Transformation temperatures and Microstructure the alloy exhibit with the variation of chemical composition.



To conclude the biocompatibility of the alloy using turbido-metric test.

Chapter 3 Experimental procedure These alloys are extensively used in numerous medical applications such as orthopaedic applications i.e. femoral shaft fracture and several expatriated femoral neck of the leg, dental implants, and stents reducing the likelihoods of heart attacks. For the evaluation of biocompatibility, the bacterial strains E.Coli and S.Aureus were chosen during the test. S. Aureus is a gram-positive bacteria which is round in shape and can be found in marine species as well as human respiratory system and Escherichia Coli is a gram-negative bacteria in the form of cylindrical rod shape which exists inside the small intestine of warm-blooded organisms.

The growth of the bacteria was witnessed on the surface of Petri plates which can be measured by calculating the units of colonies that look like punctiform (a dot-like structure). A single dot on the surface of the Petri plates represents a single colony where a group of bacteria resides. These colonies are evident with naked eyes and can be counted manually. The number of colonies formed is recognised as colony forming unit (cfu). The purpose of the present work is to conclude the biocompatibility of Cu–Al –Mn Shape memory alloy by making use of invitro antibacterial study where turbidity test method is taken into consideration and to determine the cfu value

3.1 Preparation of Alloy The alloys were prepared by taking fine Copper, Aluminium and Manganese in the right amount of 100 grams in a graphite crucible and then kept for melting inside the induction furnace. The molten blend is then decanted into the moulds and allowed to solidify. 2 flat newly casted samples were taken for the experiment and they were subjected to homogenization at 900°c for half hour. In order to attain the required dimension of 1mm thickness, the samples were subjected to hot rolling. They were heated inside a resistance furnace for around 900°c and then rolled using a rolling machine until they are 1mm thick. The samples were Betatized to eradicate the impurities present followed by step quenching in hot water (100°c) for 5 minutes and then quenched in cold water (30°c) for 2 minutes. The samples were subjected to bend test to determine the percentage SME of all the alloy samples of 50mm x 20mm x 1mm

(length x width x thickness) dimensions. They were then analysed for microstructure under an optical magnifying instrument after they were deburred and polished.

a

b

c

Fig. 10. (a) Induction Furnace; (b) Resistance Furnace; (c) Roller.

3.2 Antibacterial test 3.3.1 Preparation of Luria Bertani Broth, Nutrient Broth, and Muller Hilton Broth About 0.65g of Nutrient broth, 1.25g of Luria Bertani broth and 15.2g of Muller Hilton broth are taken in a discrete conical flask along with distilled water of 50ml, 50ml and 400ml which was blended thoroughly to prepare the broth and diluted using 1 litre of distilled water.

3.3.2 In-vitro antibacterial activity by using turbidity method In this present work, Staphylococcus aureus and Escherichia coli are taken for the antibacterial assessment. The purely cultured microorganisms were subcultured on the nutrient broth by rotating at 200RPM (Rotation per Minute) by means of Rotary shaker at temperature 37°c until absorbance range of 0.4 to 0.6 at 600 Nm is achieved, to verify the cells were in exponential form. During the conduction of the experiment, freshly cut deburred samples of the alloy of dimensions 10x10x1mm were placed into the test tubes along with 5 ml of bacterial suspension and kept on the rotary shaker. The test tubes were then placed inside the incubator for 3 hours at 37°c. These alloy samples were taken out of the test tubes and swabbed 2 to 3 times in Phosphate supported saline in order to remove the bacteria adhered to them. After swabbing the samples were again put into new test tubes containing phosphate cradled saline, and gyrated to remove the bacteria stuck on the samples.

a

b

c

Fig. 11. (a) Rotary shaker; (b) Autoclaving; (c) Incubation chamber. [3]

The prepared Muller Hilton agar Medium were decanted and allowed to solidify on the Petri plates. Later the cfu are determined by manual counting of the growth. By serial dilution (106

dilution) process, the bacterial growths are computed and finally plated on the sterile Petri

plates using control. After 18-24 hours of incubation at 37°c, these plates were visually examined to determine the number of colonies. The autoclaving was used to free the bacteria from test tubes, LB broth, NB broth and PBS.

Fig. 12. Serial dilution process [3].

Chapter 4 Result and Disscusions 4.1 Chemical composition The chemical composition is determined using the optical emission spectrophotometer which has the capability to provide the composition up to second decimal point. The compositions are shown in table 1. Table 1. The alloy compositions are shown below

4.2 Shape memory effect (SME) Shape memory effect is the phenomenon of restoring the shape of a plastically deformed alloy by heating it above austenitic temperature. To perform this test a tube of diameter of 32mm is used and the specimen of dimensions 50mm*20mm*1mm is bent around it as displayed in figure 4. Upon unloading it recovers angle 𝜃𝑚 and after heating it above austenitic temperature, gains its original shape. The percentage gain due to SME is given by the following equation: θm

% SME = 180º−θe 𝜃m= angle recovered on unloading 𝜃e = angle recovered on heating.

Fig 13. Schematic illustration of Bend Test [3]. The expansion of ternary combination that is the Manganese determines the SME as it plays a vital role during change of phase from martensitic to austenite and furthermore in martensitic arrangement as given in table 2. Table 2. Percentage SME Showed by the specimen during bend test

Sample

d(mm)

t(mm)

ᶿm

SME%

CAM 1

32

1

141

94

CAM 2

32

1

134

89

CAM 3

32

1

149

82

4.3 Microstructure Microstructure gives the detailed view of the grain boundaries and their orientations. Before the assessment, the samples were polished and deburred using different grades of emery papers which gives them a smooth finish and fine surface wrap up. Furthermore, these samples were etched with a Keller’s reagent and then viewed through an optical microscope.

a

b

c

d

Fig 14. Microstructure The Austenitic arrange is shown in Fig 5.a and 5.b, while Fig 5.c and 5.d shows the Martensite arrange (strip write) acquired upon step smothering. 4.4 Differential Scanning Calorimeter Ms, Mf, As, and Af is the Transformation Temperatures of the alloys which were determined using DSC Q200 V24.11 Build 124 Differential Scanning Calorimeter by passing N2 gas. Before the test, the samples went through preliminary checks to define the range of transformation temperatures, which lies between 30°c to 200°c. A warming and cooling rates of 10K/min were taken to be ideal conditions for the DSC test. The rate of cooling was restricted to a rate of 10K/min as at greater rates the region of MS and Mf ends up incomprehensible because of the reduction of the reaction time of the instruments. A curve was obtained by plotting the temperature against the heat flow. These curves show that the

Transformation temperature As, Af, Ms and Mf were found to be, 25.8 ˚C and 43.1˚C, 2.8and 20.4˚C respectively.

0.07 0.06

0.05 0.04

HEAT FLOW

0.03 0.02 0.01 0 -0.01

0

20

40

60

80

100

120

140

160

180

-0.02 -0.03 -0.04 -0.05 -0.06

-0.07

TEMPERATURE °C

Fig `15. DSC plot 4.5 Transformation Temperatures Among the few distinct methodologies that exist to decide the Transformation temperatures of a shape memory alloy, the eminent are the Digital scanning calorimetry, consistent load estimation and dynamic Af estimation. The last two technique uses the combinations of development during the warming and cooling and needs a precise approximation of both the temperatures and the relative alteration. Differential Scanning Calorimeter (DSC) is the exact one for defining the transformation temperatures at zero load condition. The plot shown in Fig 6. Were acquired by estimating the range of heat absorbed and radiated during the phase change. Although DSC yields repeatable and exact results, it can now be questionable if there is a ton of leftover work inside the mishmash.

Table.3. Transformation Temperatures of Cu-Al-Mn SMAs

Transformation Temperatures (˚C)

Alloy ID Cu-Al-Mn

Mf

Ms

As

Af

CAM 1

2.8

20.4

25.8

43.1

CAM 2

6.5

21.8

30

48.2

CAM 3

35

56

58

80

4.6 Antibacterial test of Cu-Al-Mn SMA’s

Bacteria

Alloy ID

Control

10-5

10-6

I

II

III

I

II

III

CAM1

E.coli

CAM2

CAM1

I

II

III

I

II

III

S.aureus

CAM2

Fig.16. shows the formation of colonies for S.Aureus bacteria and E.Coli bacteria on the petri plates.

4.7 Calculating Colonies that Arose On Petri Plates by Visual Assessment:

Table.4. Manually counted colonies formed on the petri plates

Alloy ID

S.aureus

E.coli 1,200cfu/ml

CONTROL

1,160 cfu/ml

10-5

10-6

10-5

10-6

CAM 1

580

300

466

78

CAM 2

476

206

116

54

In control plate, it was detected that the number of variable colonies of E.coli were 1200cfu/ml while in dilutions 10-5 and 10-6the number of variable colonies in CAM1 are 580 and 300 cfu/ml and in CAM2 476and 260cfu/ml respectively for growth of E.coli. This observation implies that the alloy as a supporting material for the growth of E.coli. Similarly, the growth of S.aureus was witnessed in control sample as well as treated sample (Cu-Al-Mn). It was observed that in the control the no. of variable colonies are 1160cfu/ml

whereas in the treated sample i.e. in CAM1 the colonies appeared were 466 and 78cfu/ml. For CAM2 the colonies counted were 116 and 54cfu/ml respectively. 4.8 Macroscopic counting of colonies The colonies formed on Petri plate are visible through the naked eye and can be determined by manually counting them.

Fig. 17.Manual counting of colonies.

Chapter 5 Conclusions  The shape memory effect was perceived in the alloys which was around 94%  There is a variation in Percentage SME of Cu-Al-Mn shape memory alloy with the variation of chemical composition.  It requires less time and expenditure to synthesize Cu-Al-Mn SMAs using ingot metallurgy.  The transformation temperatures differ with the variation of chemical composition of the alloys.  The alloys showed a remarkable biocompatibility for both gram positive and gram negative bacteria when they were investigated for biocompatibility by turbido-metric. This concludes that the alloys synthesized are applicable for invitro uses.

Scope for Future Work Shape Memory Alloy has a wide range of applications in various fields. It has found its application in various fields like automobiles, medical, marine, space exploration, medical instruments, human embed and future progress material. The mechanical property of SMAs has an indispensable part while designing a product. These properties helped in fabricating products that are way better than products made out of conventional materials. It provided an entry way for various applications which was not conceivable using conventional materials there by helping researchers to solve new problems and meanwhile get flexibility the assurance of the material with more significant utilize and viable system for working up these combinations. Less work has been done on the depiction of utilization direct of these SMAs needs watchful research before implanting it into individual and in not all that inaccessible future; it will swap Nitinol for supplements.

References [1] Gupta, , P Seena, Parbin K, Dr.Rai, R. N., “Studies on shape memory alloys –A review”, International Journal of Advanced Engineering Technology, Vol.III, Issue I, pp. 378-382, 2012. [2] Fatiha El Feninat , MichelFiset, GaetanLaroche, and Diego Mantovani , “Shape Memory Materials for Biomedical Applications”, Advanced Engineering Materials, 4,No. 3, pp.91-104, 2002. [3] Hironari Taniguchi, “Flexible Artificial Muscle Actuator Using Coiled Shape Memory Alloy Wires”, APCBEE Procedia, 7, pp. 54 – 59, 2013. [4] Kenneth Kanayo Alaneme, Eloho Anita Okotete, “Reconciling viability and costeffective shape memory alloy options – A review of copper and iron based shape memory metallic systems”, Engineering Science and Technology, An International Journal 19, pp. 1582–1592, 2016. [5] AksuCanbay, Z.YakuphanogluF, C. Karagoz, “Controlling of Transformation Temperatures of Cu–Al–Mn Shape Memory Alloys by Chemical Composition”, ActaPhysicaPolonica, A, Vol. 125 Issue 5, pp.1163-1166. 4p, May 2014. [6] Raju G. Kammula and Janine M. Morris, “considerations for the biocompatibility evaluation of medical devices,” MDDI online, May 2001. [7] Gupta, Parbin K a, P Seena b, Dr. Rai, R. N, “STUDIES ON SHAPE MEMORY ALLOYS –A REVIEW”, International Journal of Advanced Engineering Technology (E-ISSN 0976-3945). [8] Shivasiddaramaiah A.G., U.S.Mallikarjun, and Prashantha S, “Synthesis and characterization of Cu-Al-Be-Mn Shape Memory Alloys Prepared by Induction Melting Technique”, Applied Mechanics and Materials Vols.813-814 (2015) pp 240245. [9] Shivasiddaramaiah A.G., Manjunath.S.Y, Prasanth Singh, U.S.Mallikarjun, “Synthesis and Evaluation of Mechanical Properties of Cu-Al- Be-Mn

Quaternary

Shape

Memory Alloys”, International Journal of Applied Engineering Research, ISSN 09734562 vol.10 No.55 (2015). [10]

A.G Shivasiddaramaiah, U S Mallikarjuna, Praveen N, Prashantha S,

C.Anupama, “Evaluation of Biocompatibility of Cu-Al-Be-Mn Quaternary Shape

Memory Alloy” International Conference on Advances in Materials and Manufacturing Applications [IConAMMA 2017]. [11]

Shivasiddaramaiah A.G., Ravi Das B.R.D, Prasanth Singh, U.S.Mallikarjun,

“Study on Corrosion Behaviour of Cu-Al-Be-Mn Quaternary Shape Memory Alloys At Room Temperature”, International Journal of Applied Engineering Research, ISSN 0973-4562 vol.10 No.55 (2015). [12]

Vybhavi ShivaKumar,

A.G shivasiddaramiah, C. Shashishekar, U.S

Mallikarjun “Studies on the biocompatibility of shape memory alloys: A review” 5th International Conference on Applied Science Engineering and Technology (ICASET18). [13]

Y.F.Zheng, B.B.Zhang, B.L.Wang, L.Li, Q.B.Yang, L.S.Cug,, “Introduction of

Antibacterial Function Into Biomedical Ti Ni Shape

Memory Alloy By The

Addition of Element Ag”, Acta Biomaterialia 7 (2011) 2758–2767.