WEAR BEHAVIOR AND MICROSTRUCTURAL …624 Int. J. Mech. Eng. & Rob. Res. 2014 Tarun M S et al., 2014 WEAR BEHAVIOR AND MICROSTRUCTURAL ANALYSIS OF COMMERCIALLY PURE TI AND ITS ALLOYS

624

Int. J. Mech. Eng. & Rob. Res. 2014 Tarun M S et al., 2014

WEAR BEHAVIOR AND MICROSTRUCTURAL

ANALYSIS OF COMMERCIALLY PURE TI AND ITS

ALLOYS ON DRY SLIDING: A REVIEW

Tarun M S1*, Roshni Sambrani2 and Aadarsh Mishra3

*Corresponding Author: Tarun M S � [email protected]

Titanium and its alloys exhibit a unique combination of physical and corrosion resistance propertieswhich make them ideal materials for space flight engine component such as disks and blades ofcompressor, marine applications, chemical industries and many bio medical applications. Howeverthe use of these materials is limited due to its poor tribological properties. Because of this reason,these materials are of much interest to the researchers from few decades and they were subjectedto many experiments to explore the wear behavior to a maximum extent. In this paper an attempthas been made to consolidate some aspect of wear behavior of CP Ti and factors affecting thewear mechanism.

Keywords: CP Titanium, Ti-6Al-4V, Strain rate response, Tribo-oxidation, Mechanically mixedlayer, Dry sliding behavior

INTRODUCTION

Titanium alloys are being increasingly used inaerospace and automobile industries owing totheir enhanced properties such as high strengthto weight ratio, corrosion resistivity, tensilestrength at room and elevated temperatures,wear resistance combined with significantweight savings over unreinforced alloys.

These materials have gained a lot ofcommercial importance in places where thereis a requirement of high strength and density(Collings E W, 1984)). But these materials are

ISSN 2278 – 0149 www.ijmerr.com

Vol. 3, No. 3, July 2014

© 2014 IJMERR. All Rights Reserved

Int. J. Mech. Eng. & Rob. Res. 2014

1 Department of Mechanical Engineering, National Institute of Technology Calicut 673601, India.

2 Department of Mechanical Engineering, National Institute of Technology, Surathkal.

3 Department of Mechanical Engineering, Manipal Institute of Technology, Manipal University, Manipal, Karnataka-576104.

observed to have a low siding wear resistanceowing to their low resistance to plastic shearingand the poor protection provided by thesurface oxides (Budinski K G, xxxx;Yerramareddy S and Bahadur S, 1992; EyreT S and Alsahin H, 1977). With a view toimprove the wear resistance there are anumber of surface modification treatmentsbeing developed (Bell et al., 1986).

Wear is a process of damage thatgenerally involves progressive loss of materialdue to mechanical contact of matter. Wear is

Research Paper

625


quantified by the term wear rate which isdefined as the mass or volume or height lossof material removed per unit time or slidingdistance. Wear phenomena can becharacterized in to two main groups dependingup on the mode of interaction of the contactsurfaces (Jahanmir S, 1978). In first group,wear mechanism is dominated by mechanicalinteraction which includes adhesion, abrasion,delamination, impact wear and surface fatigue,etc. Second group is primarily dominated bychemical interaction which includes corrosivewear, diffusive wear and oxidative wear.

The characteristics features and definitionsof different wear mechanisms are given inTable 1.

Another method of classification of weardepends on the intensity of material loss. Suchclassification asmild wear and severe wear,

is based on scale size of wear debris. In mildwear, wear occurs at the outer surface layersand worn debris contains fine oxide particlesof size vary from 0.01 nm to 100 nm. In severewear, wear occurs at deep surfaces and sizeof wear debris ranges from 100 nm to 100 µm.

Nagaraj and Kailas studied the effect ofstrain rate response approach and tribooxidation to explain the wear and frictionbehavior of Ti. (Kailas S V and Biswas S K,1995; Kailas S V and Biswas S K, 1997;Kailas S V and Biswas S K, 1999). Strain rateresponse approach is associated withmicrostructural response of metal to imposedcondition of strain, strain rate and temperature.Microstructural response is mainly based onDynamics Material Model (DMM). DMM isbased up on the principle that the efficiencyby which the material dissipates power

Mechacnism Definition Characteristics

Adhesion Wear due to transfer of material from Adhesion bonding, shearing and material

one surface to another surface by transfer

shearing of solid welded junctions of asperity

Abrasion Wear due to hard particles or proturburence Ploughing, wedging and cutting

sliding along a soft solid surface

Delamination Wear caused by delamination of thin material Plastic deformation, crack nucleation and

sheets beneath the interface in the subsurface propagation

Erosion Wear due to mechanical interaction between Angle of incidence, large scale subsurface

solid surface and a fluid, or impinging liquid deformation, crack initiation and nucleation.

or solid particle.

Fretting Wear due to small amplitude oscillatory Relative displacement, amplitude and

tangential movement between two surfaces entrapment of wear particle

Fatigue Wear caused by fracture arising from Cyclic loading and fatigue crack propagation

surface fatigue

Oxidation Wear takes place when sliding occurs in Formation of weak, mechanically incompatible

oxidative environment oxide layer.

Table 1: Characteristics Features of Different Wear Mechanisims

626


decides its microstructural response. Thepower involved during plastic deformation isgiven by P=σE. According to DMM (Prasad YV R K et al., 1984; Prasad Y V R K andSeshacharyalu T, 1998), this power isconsumed in heat dissipation andmicrostructural changes. This powerpartitioning is decided by strain rate sensitivityof flow stress (m) of the material. The variousmicrostructural responses of material includeAdiabatic Shear Banding (ASB), flow banding(FB), twining, dynamics recrystallization, andsuper plasticity. Narrow shear bands occurquite frequently in a variety of materials underdynamic loadings and are usually termed asadiabatic shear bands (ASB) (Rogers H C,1979; Bai Y L, 1990). These bands relateclosely to failure and cracking in structuralmaterials (Xu et al., 1989; Meyer L W et al.,1994). For a given metal or alloy the specificmicrostructural evolution was found to berelated to the imposed strain rate andtemperature and therefore designated asstrain rate response. This frame of work maybe extended to a wear situation, as in thesubsurface regions a large gradient of strainexists (Kailas S V and Biswas S K, 1995;Kailas S V and Biswas S K, 1997; Kailas S Vand Biswas S K, 1999). Adiabatic ShearBanding (ASB) is a microstructural mechanismthat promotes cracking. A particularcombination of strain rate and temperatureoccur in surface which results in deleteriousstrain rate response where crack is nucleatedand propagated. In titanium it wasexperimentally observed that wear rate reduceswith increase in sliding speed. This is due toreduction in the intensity of ASB in near surfaceregion of titanium pin (Kailas S V and BiswasS K, 1997). ASB depends on many factorssuch as abrasive particles, temperingtemperature, number of impact etc.

Figure 1 shows the strain rate microstructuralresponse map for titanium obtained from theuniaxial compression tests done at variousconstant true strain rates and temperatures.The curves represent the strain rates andtemperatures estimated in the subsurface ofthe titanium pin at various sliding speeds anddepths.

In case of titanium, Kailas and Biswas(1995) observed experimentally that wear ratereduces with an increase in sliding speed.This was postulated to be due to the reductionin the intensity of ASB (microstructuralinstability) in near-surface regions of thetitanium pin. Strain rate response approachmade a good correlation between the wearrate and microstructural evolution in the near-surface region (Kailas S V, 2003).

Under ambient condition, the materialresponds to the increase in potential energydue to friction by thermal oxidation. For manymetals and alloys, there is a transitiontemperature (either ambient temperature orsurface temperature due to frictional heat)above which the wear rate in the mild wearregime becomes very low compared with thecorresponding rate at lower ambient or surface

Figure 1: Microstructural ResponseMap for Titanium

627


temperatures (Stott F H et al., 1985; Smith A F,1986; Newman P T and Skinner J, 1986). Thisis due to the establishment of a continuousoxide layer (sometimes known as a ‘glaze’)which gives reduced resistance to sliding andgood protection against wear damage.Thisoxide layer acts as a solid lubricant andprevents further metal to metal contact thusreducing co-efficient of friction and wear rate.In titanium presence of TiO2 layer reduce theco-efficient of friction from 0.75 to 0.40 byavoiding direct contact between titanium andother surface (Hong H et al., 1988). I.I Garbarshowed that as normal load increases, tribo-oxidation is accompanied by the mechanismof plastic deformation (Garbar I I, 2002).

Mao et al. (Cui et al., 2012) explained thatTribo-layer, a mechanical mixing layer existedon worn surfaces under various conditions.However, the protective role of tribo-layerdepended on whether more oxides appearedor not. The Mechanically Mixed Layer withmore oxides gave an obviously protective roledue to its high hardness. In the case of materiallike titanium alloys, most wear mechanismobserved are consistent with Archard adhesivewear characteristics by plastic ploughing andtransfer of material from the counterface. Withrespect to friction and wear behavior,numerous authors(Perrin and Rainforth, 1995,Leonard et al., 1997, Jiang and Tan, 1996,How and Baker, 1997 and Rigney, 1998) haveconcluded that the tribological behavior isinfluenced by the mechanical, physical andchemical properties of these near-surfacematerials. In all case, a mechanically mixedlayer (MML), otherwise called Tribo layer, waspresent in most dry worn wrought titaniumalloys due to the repetitive sliding.(checkcontinuity of para

The purpose of this paper is to come to thegeneral understanding of wear mechanismsby reviewing the characteristics of wear CP Tiand summarizing the factors affecting the wearmechanisms of Ti.

WEAR BEHAVIOR OF TI

Figure 2 shows the variation of wear rate withsliding speed of CP Ti sliding against aluminadisk under ambient conditions. Under ambientconditionsthey noticed that wear rate is highat speed of 0.01m/s; this can be attributed tothe high intensity of ASB due to lowtemperature which initiates crack nucleationand propagation and lack of tribo oxidation.But at 0.1m/s, 0.5m/s and 1.0m/s wear rate isfound to be low. This is due to the tribo oxidationand MML formation. As speed increases, theflow of ASB become in homogenous mannerand interface temperature increases whichresult in tribo oxidation. In tribo oxidation a thinoxide layer of several micron thicknessesproduced over metallic surface in slidingcontact. This oxide layer acts as a solid

Figure 2: Shows Wear Rate of Pure Tiwith Sliding Speed for Normal Load of

(a) 15.3N (b) 45.8N (c) 76N underAmbient Conditions [24]

628


lubricant and prevents further metal to metalcontact thus reducing wear rate. Theprotecting nature of oxide is due to its highthermal stability and better hardnesscompared to that of base materials. Thepresence of oxide at these speeds isconfirmed by surface micrograph of Ti pinalong the sliding direction at constant load asshown in Figure 5. During sliding of metalsMechanically Mixed Layer formation is causedby the chemical reaction and mechanicalmixing of oxides and base materials. Thehardness of MML depends upon the amountof oxides present in it. It is seen that amount ofoxides increases with the speed which is thereason for increase in its hardness andprotecting nature. This is due to the mixing ofoxides and base material at highertemperature induced because of higherspeed. Thus we can say that more amount ofoxide compound in Mechanically Mixed Layer,for eg TiO

2, will increase the hardness of MML

hence will improve the wear property of thematerial. The amount of oxides and hardnessof Mechanically Mixed Layer depends uponthe temperature, which in turn is a function ofspeed and load. Figure 4 shows the EDS lineanalysis of tribo-layer of Ti–6Al–4V alloy slidingunder various conditions (Cui et al., 2012). Itcan be noticed that various oxide such as TiO2

and Fe2O

3 exists on the pin surface of Ti-6Al-

4V. The hardness and material properties ofoxide and MML layer is different from that ofbase metal which results in better wearbehavior. Thus oxide amount and hardness ofMML play main role in friction and wearbehavior.

Figure 3 shows the wear rate of Pure Ti withsliding speed for different normal load under

Figure 3: Shows Wear Rate of Pure Tiwith Sliding Speed for Normal Load of

(a) 15.3N (b) 45.8N (c) 76N underVacuum Conditions [24]

Figure 4: EDS Line Analysis of Tribo-layerof Ti-6Al-4V Alloy Sliding Under VariousConditions:(a)25 1C, 100N;(b)200 1C,

100N;(c)400 1C, 100N; and(d)500 1C, 100N. [23]

vacuum conditions. Under vacuum conditionsthey noticed that the wear rate is quiet highercompared to that in ambient conditions for allspeeds; this can be attributed to the lack oftribo oxidation and MML, high temperature

629


Figure 5: Worn Surface of Pure Ti Slid with Normal Load of 15.3N UnderAmbient Conditions at Sliding Speed of (a) 0.01m/s and (b) 1.0m/s[24]

Figure 6: Wear Debris of Ti Slid at Normal Load of 45.8Nwith Sliding Speed of (a) 0.01m/s and (b) 1.0m/s [24]

Figure 7: Worn Surface of Pure Ti Slid with Normal Load of 45.3N UnderVacuum Conditions at Sliding Speed of (a) 0.01m/s and (b) 1.0m/s [24]

630


which will cause large plastic deformation andhigh surface energy of adhesion in vacuumconditions. The clean surface in vacuumconditions results in high surface energy ofadhesion. Hard asperities, plowing over asofter surface of the pin without cutting willproduce ridges. Ridges can then be flattenedby further contact. As a result extrusions or lipsare formed. These lips are broken off andbecome flat wear flakes. One of the feature insubsurface micrograph under vacuumconditions that is different from the subsurfacemicrograph under ambient conditions is thatat 1.0m/s a ‘beard’ is seen under vacuumconditions (Figure 7). This ‘beard’ like featureis a clear indication of very large plasticdeformations near the surface regions. Thesqueezing of the high temperature materialresults in the formation of the ‘beard’ and thewear debris with large size.

FACTORS AFFECTING WEAR

BEHAVIOR

Effect of normal load

Rabinowicz [25] showed experimentally thatwear loss of copper is proportional to appliednormal load when sliding against steel. Hereasoned that increasing the normal loadresults in an increase in the number ofadhesive junctions and an increase in wearrate of copper. It was observed by Archard [26]that, there was a transition from mild to severewear, when the contact pressure reached tovalue of about one third of hardness of metals.This was attributed to the interaction of plasticzones that occurred beneath the contactingasperities. In high load regime, mechanicaldamage of material occurs due to high surfacestresses. It was observed that an increase in

load results in monotonic increase in interfacetemperature, which led to the reduction of theyield stress of a material. Hence, it could beconcluded that the wear rate of material was alinear function of normal load. However, it wasalso observed that rate of increase in wear ratedid not remain constant over the long range ofnormal load.

Effect of Sliding Velocity

Experiments were conducted by Suh et a1 [27]under ambient conditions on commerciallypure titanium using pin on-ring geometry. Adecrease in wear rate of Ti was observed withthe increase of sliding speed. He reasonedthat due to the increase in temperature, thedrop in wear rate occurred as there was anincreased resistance of the material to cracknucleation and propagation. The amount offrictional heat that is generated during drysliding condition, with the increasing slidingspeed increases, this leads to the tribo-oxidation, which forms an oxide layer at theinterface. This oxide film serves as lubricantwhich reduces the wear rate of metals. In thecase of lubricated condition, at higher slidingspeed, the formation of hydrodynamic lubricantfilm at the interface minimizes the wear rate.Generally, wear rate of metals shows adecreasing trend with sliding speed in dry aswell as lubricated sliding conditions. However,if interfacial temperature reaches the meltingpoint of a metal, it lowers the hardness of themetals drastically and causes severe wear.

Effect of Temperature

The temperature is an important parameter,which influences the wear response of metalin the following way.

631


1. It accelerates the chemical reactivity of ametal surface.

2. The physical and the mechanical propertiesof the metals are altered.

3. It changes the microstructural response too.

Deanley P A and Dahm K L (2004) studiedthe wear behavior of thermally oxidized anduntreated pure titanium’s samples. He foundthat wear rate of untreated titanium is greaterthan that of thermally oxidized titanium. Thushe reached to a conclusion that the generationof the TiO

2 layer provided protection by

interfacial fracture. Hence it is understood thatthermal induced oxidation reduces the wearrate of metals. Rabinowicz (1980) performedsliding tests on cobalt-steel pair at differenttemperatures. He observed the wear rate at653 K to be nearly 100 times than that observedat 553K. The reason attributed to this increaseis the phase transformation from HCP to FCCstructure.

In dry sliding, temperature is a function ofspeed and load. Higher speed or/and higherload result in high temperature. Thus we cansay that wear behavior is governed bytemperature which in turn is a function of speedand load.

Effect of Environment

Hutching et al. (Hutching I M, 1992) studiedthe influence of environment on wear behaviorof commercially pure titanium. He observedthat titanium exhibited a linear wear behaviorunder ambient conditions, but a linear behaviorwas not observed in inert gas atmosphere. Heobserved that titanium exhibits high wear ratein an inert atmosphere which was due tosevere adhesion and material transfer. Inambient conditions, the wear rate of metals

can be lower than in inert atmosphere only ifthe oxide film is strong enough to prevent thedirect contact between metal-metal surfaces.One could expect that wear rate of metals ishigher in vacuum than in air. But the oppositeis also true. Rigney[30] observed that wear andfriction of lead and babbit alloys are high invacuum than air. He concluded that formationof fine-grained layer in air induces non-uniformsliding which causes high friction and wear.

Effect of Hardness

According to the Archard model (Rigney D A,1997), the wear rate of metals is an inversefunction of their hardness. Harder materialscan provide better resistance to cutting andpenetration. In the case of abrasive wear, it iseasy to correlate hardness with wear rate as itinvolves penetration process. Kruschov et al.[32] studied the relative wear resistance ofpure metals and cold worked steels as afunction of hardness in two-body abrasion.There was no effect of prior work hardeningreported on wear rate. The effect of hardnesson sliding wear is quite complex to understood.Transfer of metal and mechanical mixing areone of the few complex processes that occurduring sliding wear, and these processesmodify the relative hardness of sliding metals,which makes the effect of hardness on wearprocess difficult to understand.

The hardness of the mixed material may begreater or lesser than that of parent metals.The heterogeneous nature of the mixedmaterial varies hardness locally. Kato et a1 [33]indicated that the sliding behavior of differentmetal pairs correlates well with a simplehardness ratio given by R = Hd /Hp (Hd,Hp-Hardness of disc and pin, respectively) Heobserved that severe wear occurs when R

632


value is below 1 and mild weal occurs when Rat any time during the sliding test has a valueabove 1.

Effect of Elastic Modulus

Obeile et al. (1951) pointed out that a bettermeasure of abrasive wear resistance is theamount of elastic deformation that surface cansustain. He related the abrasive nearresistance of a material to elastic modulus byH/E ratio. Thus, the wear resistance of materialcan increased by either by increasing thehardness or decreasing the elastic modulus.The high elastic modulus produces high contactstresses, which decreases the wearresistance of a material. On the other hand,Khrushov (1974) anticipated Oberle et al’smodel and assumed that wear resistance of amaterial is directly related to elastic modulusin accordance with adhesive theory of wear.He explained that metals, which have highelastic modulus result in decrease of real areaof contact leading to low adhesion and wear.

Effect of Fracture Toughness

Brittle materials like ceramics have a highgood wear resistance owing to the high fracturetoughness. During interaction of asperities,crack growth occurs with critical amount ofstrain. If the applied strain is smaller thancritical strain, the wear rate of a metal isindependent of fracture toughness. Once thecritical strain is reached, there is an increasedprobability of crack growth and wear rate ofmetals depends up on fracture toughness.Hornbogen [35] proposed the model that thereare three regions of wear behavior as afunction of fracture toughness. In first region,wear is not affected by toughness in whichArchard’s law is obeyed Second region

involves transition from mild to severe wear.Increase in pressure, strain rate or a decreasein fracture toughness are the factors whichinduce such a transition. Third region involvesa highly brittle condition which shows high wearrate because of low fracture toughness.

Effect of Crystal Structure

Sliding of metals produce large plasticdeformation, which in turn forms dislocationcell wall structures near the surface regionSince cell walls serve as pathway forsubsurface cracks, metals with limited numberof slip systems (HCP) exhibit lower wear ratethan metals with large number of slip systems(FCC). Buckley (1978) showed experimentallythat cubic crystals wear at about twice the rateof hexagonal crystals. While most hexagonalmetals have good friction and wear properties,however Titanium, although a hexagonal metal,exhibits relatively high friction and wear. Thishigh friction may be related to a difference inthe slip mechanisms for Titanium; titaniumunlike most hexagonal metals slips on the {101-

0} planes rather than on the (0001) basal plane

Effect of Thermal Diffusivity

Low thermal diffusivity makes the dissipationof heat from the interface difficult. Themechanical strength of the metals is degradedby the thermal accumulation and this in turnleads to high wear.Wear and thermal diffusivityare inversely related. Abdel-Aal (2000) relatedthe heat dissipation capacity of metals withwear transition. He postulated that transitionfrom mild to severe wear occurs once thequantity of heat generated is higher than thequantity of heat dissipated. He also noted thatif the amount of thermal accumulation reachesa critical value, delamination of oxide flakeresults in higher wear rate.

633


CONCLUSION

From this study we can conclude that wearbehavior of CP Ti is not its material property. Itdepends on operating conditions such assliding speed, normal load, temperature,environment conditions etc. and materialparameters such as hardness, elastic modulus,crystal structure etc. One interesting thing tobe noted in dry sliding behavior of Ti is thatunder ambient conditions at higher load andhigher speed tribo oxidation and MechanicallyMixed Layer (MML) formation take placewhich protects the surface but the samecondition under vacuum conditions leads tolarge deformation and large wear out ofsurface. Thus in industrial application we canimprove the tribological behavior of Ti byselecting proper operating conditions.

REFERENCES

1. Abdel-Aal H A (2000), Journal ofTribology, Vol. 122, pp. 657-660.

2. Archard J E (1956), Royal Soc., London,A Vol. 236, pp. 397-410.

3. Archard J F (1953), Journal of AppliedPhysics, Vol. 24, pp. 981-988,

4. Bai Y L (1990), Adiabatic shear banding,Res. Mec & 31, pp. 133-203.

5. Bell T, Bergmann H W, Lanagan J, MortonP H and Staines A M (1986), Surf. Eng.2, pp. 133–143.

6. Buckley D H (1978), Wear, Vol. 46, pp.19-53.

7. Budinski K G (xxxx), Wear 151 _1991.pp. 203–217.

8. Collings E W (1984), “The Physical

Metallurgy of Titanium Alloys”, ASM,Metals Park, OH.

9. Cui X H, Mao Y S, Wei M X and Wang SQ (2012), “Wear characteristics of Ti-6Al-4V Alloy at 20–400°C, TribologyTransactions”, Vol. 55, No. 2, pp. 185–190.

10. Deanley P A and Dahm K L (2004),Wear, Vol. 256, pp. 469-479.

11. Eyre T S and Alsahin H (1977), “Proc. Int.Conf. on Wear of Materials”, ASME, NewYork, pp. 344-350.

12. Garbar I I (2002), “Gradation of oxidationwear of metals”, Tribology International,Vol. 35, pp. 749–775.

13. Hong H, Hochman R F, Quinn T J F(1988), “A new approach to the oxidationtheory of mild wear, STLE Transactions31”, pp. 71–75.

14. Hornbogen E (1975), Wear, Vol. 33, pp.251-259.

15. Hutching I M (1992), Tribology, EdwardArnold Publication, Great Britain.

16. Jahanmir S (1978), “Fundamentals ofTribology”, N P Suh and N Saha (Eds.),The MIT Press, pp. 455- 467.

17. Kailas S V (2003), “A study of the strainrate microstructural response and wearof metals”, J Mater Eng Perform, Vol. 12,No. 6, pp. 629–637.

18. Kailas S V and Biswas S K (1995), “Therole of strain rate response in plane strainabrasion of metals”, Wear, pp. 181-183,648-657.

19. Kailas S V and Biswas S K (1995), “The

634


role of strain rate response in plane strainabrasion of metals”, Wear, pp. 181–183,648–657.

20. Kailas S V and Biswas S K (1997), “Strainrate response and wear of metals”,Tribology International, Vol. 30, pp. 369-375.

21. Kailas S V and Biswas S K (1999),“Sliding wear of copper against alumina”,ASME, Journal of Tribology, Vol. 121,pp. 795–801.

22. Kato K and Hokkirigawa K (1988),Tribology Int., Vol. 21, pp. 51-57.

23. Kruschov M M (1974), Wear, Vol. 28, pp.69-88.

24. Meyer L W, Staskewisch E and BurbliesA (1994), “Adiabatic shear failure underbiaxial dynamic compression/shearloading”, Mech. Maste., Vol. 17, pp. 203.-214.

25. Nagaraj Chelliah, Satish V Kailas (2009),“Synergy between tribo-oxidation andstrain rate response on governing the drysliding wear behavior of titanium”, Wear,Vol. 266, pp. 704–712.

26. Newman P T and Skinner J (1986), Wear,pp. 112, 291.

27. Oberle T L (1951), Journal of Metals,Vol. 3, p. 438.

28. Prasad Y V R K and Seshacharyalu T

(1998), “Modelling of hot deformation formicrostructural control”, InternationalMaterial Review, Vol. 44, pp. 243–258.

29. Prasad Y V R K, Gegel H L, Doraivelu SM, Malas J C, Morgan J T, Lark K A,Barker D R (1984), “Modeling of dynamicmaterial behavior in hot deformation:forging of Ti-6242”, MetallurgicalTransactions A, Vol. 15, pp. 1883–1892.

30. Rabinowicz E (1980), “Wear ControlHandbook”, ASME, New York, p. 475.

31. Rigney D A (1997), Tribologyinternational, Vol. 30, pp. 361-367.

32. Rogers H C (1979), Adiabatic plasticdeformation, Anne. Rev. Mater. Sci., Vol.9, pp. 283-311.

33. Saka N and Suh N P (1977), Wear, Vol.41, pp. 109-125.

34. Smith A F (1986), Tribology Int., Vol. 19,p. 65.

35. Stott F H, Glascott J and Wood G C(1985), Wear, pp. 101, 311.

36. Xu Y B, Wang Z G, Huang X L, Xing Dand Bai Y L (1989), “Microstructure ofshear localization in low carbon ferrite-pearlite steel”, Mater. Sci. Eng., AII4, pp.81-87.

37. Yerramareddy S and Bahadur S (1992),Wear 142, pp. 253–261.

WEAR BEHAVIOR AND MICROSTRUCTURAL …624 Int. J. Mech. Eng. & Rob. Res. 2014 Tarun M S et al., 2014 WEAR BEHAVIOR AND MICROSTRUCTURAL ANALYSIS OF COMMERCIALLY PURE TI AND ITS ALLOYS

Documents