IJCRR - 3(2), February, 2011
Pages: 13-26
Print Article
Download XML Download PDF
TRIBOLOGY AND DEVELOPMENT OF WEAR THEORY: REVIEW AND DISCUSSION
Author: Zamri Yusoff, Shamsul Baharin Jamaludin
Category: Technology
Abstract:In this review, the classical and contemporary wear theories and wear mechanisms are
discussed. The development of wear theories are started from adhesive and abrasive to
delamination theory, mechanical mixed layer (MML) and self lubrication theory are
reviewed based on the previous reports. It was found that the adhesive and abrasive are
developed based on quantitative approach whereas the delamination, MML and self
lubrication theory are developed based on qualitative approach. Each theory has
limitation in order to explain the wear theory comprehensively because of different
testing system, composite manufacturing technique, type of reinforcement and volume
fraction, size as well as hardness. However, a consensus has been reach from a
qualitative point view. Theory of wear debris generation mechanism is the consequence
of a combination of subsurface, surface and third body dynamic behaviours. This
approach applied in order to explain the wear mechanism usually encountered such as
adhesive, two-body abrasive, three-body abrasive, oxidation and delamination. Wear
mechanism that occurred during dry siding wear of hybrid composite (multiple
reinforcement composite consist of combination of hard and soft reinforcement) is
combination of various mechanism and highly complex phenomenon. It well known
that wear is nature process that what happen at one time is function of all event that
occurred previously. Therefore, based on previous work on dry sliding wear of multiple
reinforcement composite, it might be proposed that the wear mechanism involved in
integrated wear mechanism.
Keywords: abrasive, adhesive, wear theory, delamination, mechanical mixed layer.
Full Text:
INTORDUCTION
The study of tribology has a long history, extending for several centuries before the word itself was coined in 1965.1 Tribology is the study of friction, lubrication and wear. Professor Duncan Dawson has remarked that whereas the scientific study of friction dates back some 300 years, and that of lubrication more than century, wear has received similar attention for only 50 years.2 So, wear entered the scientific arena rather more recently. Essentially, the design and construction of early machines involved large clearances and rather slow speeds of operation, with the result that, provided gross adhesion or excessive friction could be avoided, changes in dimensions of sliding parts due to wear could often be tolerated with little adverse effect on performance. However, development of high-speed internal combustion engine in the early part of twentieth centuries that provided the initial driving force for the study of wear which has grown in importance to the present day. The understanding of wear mechanisms has developed most rapidly only with the widespread use of electron microscopy and instruments methods of microanalysis over the past 30 years.1 Based on wear studies is so young and so complex, the discrepancies between theories, confusion over nomenclature, and definitions, and inconsistencies between experimental observations is inevitable. However, the foundations of wear studies now seem to be well established. Therefore, this work attempted to review and discuss the development of wear including classical and contemporary wear theories and wear mechanisms based on literature research. Development of Wear Theory Historically, the development of wear knowledge and the ability to quantitatively estimate wear made major progress in period 1950-1965.3 This is the period when the Linear Wear Law (also called the Archard equation) and Khrushov Abrasive Wear law were developed. Wear can be defined as the loss of material that occurs when two surfaces rub against each other.4 Two common forms of wear are adhesive wear5-7 and abrasive wear8-10 . The former occurs when materials of good surface finish and similar hardness are slid against each other and surface forces cause the plucking out and transfer of metallic fragments. The later occurs when abrasive particles or surface protuberances plough and cut fragments from a surface. Adhesive wear theory The first theory of adhesive wear was proposed by Archard.5 This theory was defined wear volume as function of sliding speed, normal load and material hardness. However, this theory ignored the effect of the material’s microstructure on wear and was limited to idealised sliding conditions. This theory was based on a mechanism of adhesion at the asperities and the material removal process was related to a cohesive failure of asperities. The processes of crack nucleation and subsequent growth were disregarded. With the assumption that wear particles could be described as hemispherical particles of the same radius as the contact area, Archard developed the following expression for wear rate, W (volume of material worn): W = KdP 3H (1) Where K = wear coefficient, d = sliding distance, P = applied normal load and H = bulk hardness of material. Archard concluded that the wear rate was proportional to the applied load (assuming that the average size of the contact areas and the particles were constant) and that the wear rate was independent of the apparent area of contact. The theory predicted that enhance wear resistance was associated with increase in hardness. Abrasive wear theory The abrasive wear theory was proposed by Kruschov and Babichev since 1953.8 They defined that abrasive wear occurs when friction between a metal under stress and a harder body or grain. Abrasive wear may take place during friction of a hard rough steel surface against the surface of a softer, for example, bearing metal. Abrasive wear may be due to various mechanisms which cause surface destruction such as cutting, scratching and single or repeated plastic deformation.11 According to Hutching2 mechanisms of abrasive wear can involve both plastic flow and brittle fracture. Under some circumstances plastic flow may occur alone, but both often occur together, even in materials conventionally thought of as ideally brittle. He developed models for abrasive wear separately in two groups of mechanisms; abrasive wear by plastic deformation model and abrasive wear by brittle fracture model. In the first case the hardness of the mating surface is important factor in determining its wear resistance, whereas in the second the fracture toughness is more important, although hardness still plays the role. Chawla and Chawla4 stated during abrasive wear, the surface asperities are worn down and the contact surfaces become mated as shown in Fig. 1. This reduces local contact stress because of the increase in contact area. After this initial abrasive wear, the removal of oxidized particles occurs along the surface. This generally a steady state process in as much as it requires reoxidation of the denuded surface in order to continue removing oxidized particles. The final stage of wear occurs in adhesive mode and occurs if the contact pressure increases to the point of shearing particles. The result of shear is the formation of thin plate-like wear debris sheets. Depending upon applied pressure, the sheets can result in significant material loss. In studies of two-body abrasive wear, commercial coated abrasive papers have been widely used as abrasive mating surfaces.12-15 Various relations have been proposed between the variables of the abrasion process, in which the assumption is commonly made that the number of contacting points, for a given mesh size abrasive paper, is independent of load.9,16,17 Larsen-Badse15 studied the effect of normal load on the number of contact points in the two-body abrasive wear ofmetals and found that the number of scratches made on a copper surface by silicon carbide papers was nearly proportional to the applied load. Similar observations were also found by Sin et al.7 The influence of the nominal grit size of the abrasive particles on the number of contacts was studied by Mulhearn and Samuels14, Sin et al7 and Larsen-Badse15. They found that the number of contacts per unit nominal area was inversely proportional to the square of the mean abrasive particles. Furthermore, Spurr18 studied the surface of aluminium after abrasion by silicon carbide papers. He found that the number of scratches on the abraded specimen surface was proportional to the square root of the applied load rather than directly to the load. Such a relationship was later found also by Miki and Kobayashi.19 Wang and Hutching20 reviewed the Spurr21 reports that the height distribution of the tips of abrasive particles might be normal (Gaussian) but that the abrasive particles which contact the metal surface lie only at the upper end of the normal distribution curve, which may therefore be approximated by a linear distribution over the range of interest. Based on this assumption Spurr21 developed a semi-empirical relationship between the number of contacts and readily measureable quantities, which states that the number of contacts is proportional to the square root of the ratio of the applied load to the mating surface hardness, and inversely proportional to the diameter of the particles. Full experimental results, however, were not reported by Spurr21 , leaving some doubts about the strength of the experimental evidence for this model.
Studies of abrasive wear have been done by several researchers on aluminium composite reinforced by silicon carbide.22-28 Delamination wear theory The most widely quoted adhesive wear theory is that of Archard. Archard’s adhesion theory has been widely accepted, since the phenomenological relationship between the wear volume, sliding speed, normal load and hardness is consistent with experimentally observed results. However, according to Suh6 , the theory is weak because of completely ignores the physics and physical metallurgy of metal deformation and it does not provide any insight to the wear of metals under different sliding conditions. In 1973, Suh proposed a new theory for wear of metal. He proposed that at low sliding speeds, wear debris formation could be described by a delamination theory. The theory is based on the behaviour of dislocations at the surface, sub-surface crack and void formation, and subsequent joining of cracks by shear deformation of the surface.6 Wear processes such as adhesive wear, fretting and fatigue were all related to this same mechanism. The proposed theory predicts qualitatively that the wear particle shape is likely to be thin flake-like sheets and that surface layer can undergo large plastic deformation. Suh6 stated that wear occurred by the following sequential steps: a) Cyclic plastic deformation of surface layers by normal an tangential loads, b) Crack or void nucleation in the deformed layers at inclusions or second-phase particles, c) Crack growth nearly parallel to the surface, d) Formation of thin, long wear debris particles and their removal by extension of cracks to the surface. The rate-determining mechanism of wear showed dependence on the metallurgical structure. When subsurface deformation controlled the wear rate, hardness and fracture toughness were both considered to be major influencing factors. Jahanmir and Suh29 showed that for microstructures containing hard secondphase particles, if sufficient plastic deformation occurred during sliding wear, crack nucleation was favoured at these particles. In this situation, where inter-particle spacing is an important variable, crack propagation controlled the wear rate. Void formation primarily attributed to plastic flow of the matrix around these hard particles. Void formation occurred very readily around the hard particles but crack propagation occurred very slowly. The depth at which the void nucleation was initiated and the void size tended to increase with increased friction coefficient and applied load. Studies of delamination wear mechanism on aluminium composite have been done by several researchers.30-34 For example, Wang et al33 studied the wear behaviour and microstructural changes of 20vol.%SiCw/Al composite under dry sliding using pin-on-ring configuration for a range of load (10 – 80N and sliding speed (1.34 – 5.00 m/s) prepared by squeeze casting method followed by extrusion. They found that at heavy load, volume loss is high, thedominating wear mechanisms are adhesion and delamination wear. In SiC whiskers reinforced aluminium composites, the whiskers plays an important role. At depth of about 30µm below the surface, the shear strain is more than 1.3. The large plastic strain in the deformed layers gives rise to void nucleation and subsurface crack initiation and propagation. The subsurface cracks may initiate and propagate along whisker-matrix interfaces and cause the decohasion of whisker-matrix. Crack propagation by SiC-matrix decohesion process has been observed in SiC particulate reinforced aluminium-silicon alloys.33 The cracks will link to long cracks. With removal of surface material, the cracks become nearer to the surface and the shear strain is increased, this causes the removal of the surface layers by delamination. Delamination wear and the associated nucleation of voids at SiCp/matrix interface during the dry sliding of MMC pin against a steel counterface also reported by Venkatamaran and Sundarajan.34
Mechanical Mixed Layer
It should be noted that the adhesive wear theory5 , abrasive wear theory8,12 and delamination theory6 of wear neglect the formation of the tribolayer in their treatment of wear. According to Heilmann et al35, tribolayer phenomena occurs were common in both dry and lubricated sliding wear processes and developed very early before wear debris loosed. The composition of these layers consisted of an intimate (mechanical) mixture of materials derived from both sliding materials and the loose wear debris had the same structure and composition as the transferred layer. On the worn surface of MMCs a mechanically mixed layer (MML) was present. This layer exhibited hardness approximately 6 times that of the bulk composite. There have been a number of research works into the formation of mechanically mixed layers and the nature of wear debris in dry sliding systems, especially during Al alloys sliding against ferrous alloys.36-39 Razavizadeh and Eyre37 reported that the surface layer on the worn surface of Al-Si alloys was formed by fracture and compaction of Al oxide particles during sliding wear. Iwai et al40 noted that a tribolayer was formed on an Al 2024 alloy reinforced with SiCw after a sliding distance of only 50m (40N load and sliding speed 0.1 m s-1 ). Whereas, Zhang and Alpas32 suggested that the surface layers and debris particles contained an aluminium oxide phase with an amorphous structure, in addition to the original phases of α-Fe and α-Al. In contrast, other researchers41 found little or no oxide in the wear debris produced in the sliding wear of Al-alloys in an ambient temperature. Recently, Li and Tandon40 have studied microstructural characterization of mechanically mixed layer and wear debris of Al-Si alloy and Al-Si/SiCp composite against tool steel under dry sliding conditions. They found that wear debris were mostly detached from the MML and had microstructural features similar to those of the MML. The debris and MML were comprised of mechanical mixture of ultrafine equiaxed particles, the constituents of which varied depending on the sliding load at the sliding speed used. At low load, the ultrafine structure consisted of original materials, i.e. α-Al solid solution and α-Fe from steel ring. With an increase in the sliding load, the agglomerated debris of nanocrystaline structure was incorporated with Fe-Al (Si) intermetallic compound and aluminium and iron oxides as a result of mechanical alloying and oxidation caused by the large amount of plastic deformation during the sliding process in association with frictional heating. Deuis et al41 stated the rationale of researchers in order to explain the formation of MML layer. Initially the MMC material experienced bulk deformation and the shear deformation. With increasing deformation the reinforcement particles at the wearing surface fragmented and the number of voids nucleated at the SiCp/matrix interface increased. When the void density reached a critical value, shear stability, as postulated by Rosenfield42 , was initiated at local subsurface regions. This resulted in the occurrence of turbulence plastic flow, during which time iron and iron oxide debris was mixed in the surface MMC material, resulting in the formation of the MML layer. Venkatamaran and Sundarajan34 stated that the presence MML layer most probably controlled the wear rate. The formation of wear debris was directly related to delamination wear active within this region.
Self Lubrication Theory
Apart from hard second-phases particle in soft matrix composite, a soft secondphase particles in hard and strong matrix composites are widely used in sliding bearing applications. They possess low coefficient of friction and adapt to diverse operational conditions. Tribological properties of such materials depend in the matrix and the second-phase, as well as the size, shape and concentration of the second-phase particles. The main problem is optimization of the microstructure for the best tribological performance. This task is complicated and requires theoretical analysis. Alexeyev and Jahanmir45 have attempted to develop self lubrication theory based on quantitative analysis. Slip-line field analysis of plastic deformation is used to analyze the processes of deformation and flow of the soft phase toward the sliding surface. They found a general relationship for deformation and flow of soft phase is obtained. It shows that the properties as well as size and shape of hard matrix and soft second-phase particles control the processes of deformation and flow of the soft phase as shown in Fig. 2. Solid lubrication is introduced from the solid lubricant cavities (reservoirs) dispersed within the material. These cavities are typically filled with graphite, MoS2 or soft metal such as Pb, Sn or Ag. The solid lubricant particles deform by the sliding action of the mating surface and are squeezed out toward the surface, forming a soft interfacial film. The presence of this film is believed to be responsible forthe observed low friction and reduced wear. When the solid lubricant film is worn away, the resulting increase in friction accentuates plastic deformation of the surface layer and forces more material from second-phase particles toward the surface, thus re-forming the worn film. The beneficial effect of selflubrication depends on the thickness of the film, the relative plastic properties of the film and the sublayer, and the pressure experienced by the soft film and sublayer43. Very few studies have been done on the processes of film formation and destruction.44,45 The exact mechanism for the adhesion of the film and substrate remain unclear. In order to understand the tribological behaviour of metal matrix selflubricating composite, the basic mechanism of the formation of lubricating films must be developed. The early studies of wear behaviour on self-lubricating aluminium composite using graphite as solid lubricant have been done by several researchers.46-50 However, study on the formation of lubricating film at worn and mating surface are did not discussed thoroughly until Liu et al.44 He attempted to describe the smearing process of the embedded graphite particles in aluminium 2014 alloy during sliding in great detail based on qualitative analysis by optical microscope. They found that the reduction in friction and wear of the aluminium-graphite composites is result of the embedded graphite particles during sliding, forming a lubricating film on both the tribosurface of the composite and the steel mating surface. Whereas, Alexeyev and Jahanmir47 attempted to describe the process of film formation in self-lubricating composites and deformation of the film based on quantitative analysis by the slip-line field method. The results show that the size of second-phase particles in the composite, the relative shear yield limit of the matrix and the soft phase, and the thickness of the film control the tribological performance of these composites. Lin et al49 also studied the process and tribological behaviour of Al6061/graphite particulate composite. They found that the tribological behaviour of the composite depends on the hardness of the matrix, the rate of release graphite particulates, the structure of the solid lubricating film deposited on the wearing material, and the structure of Al chip clusters
General discussion
Development of five wear theory might be summarized as shown in Fig. 3. However, in 1995, Sanino and Rack51 proposed the theory based on debris generation in order to shows the wear mechanism in integrated manner. They stated that wear debris generation mechanism is the consequence of a combination of subsurface, surface and third body dynamic behaviours. This approach applied in order to explain the wear mechanism usually encountered such as adhesive, two-body abrasive, three-body abrasive, oxidation and delamination.
Based on literatures, since year 2000, there are some research focuses on the role of soft reinforcement particle in hybrid composite.52-61 Aluminium hybrid matrix composite consist of two or more reinforcement added in aluminium matrix. The soft reinforcement likes graphite and carbon fibre, whereas the hard material likes Saffil fibre or SiC particles in hybrid composite. Some researchers have studied the sliding wear behaviour of aluminium hybrid composite found that the hybrid composite showed the best performance in wear resistance. Their result showed more stable tribo-layers on the contact surfaces of the graphitic composites compared to non-graphitic composites However, the hard constituents in the tribo-layers were the scuffing damage that they inflicted on the counterface. Wear mechanism that occurred during dry siding wear of hybrid composite (multiple reinforcement composite consist of combination of hard and soft reinforcement) is combination of various mechanism and highly complex phenomenon. It well known that wear is nature process that what happen at one time is function of all event that occurred previously. Therefore, based on previous work on dry sliding wear of multiple reinforcement composite, it might be proposed that the wear mechanism involved in integrated wear mechanism as shown in Fig. 4.
CONCLUSION
The purpose of this paper was to highlight the development of wear theory since 1950’s up to contemporary theory. It can be concluded as follow: Adhesive wear is influenced by critical parameters such as applied load, speed and environment. Abrasive theory is influenced by contact geometry, matrix and hard reinforcement phase as well as interface characteristics. Delamination theory is influenced by changing of subsurface behavior because of load, speed, fracture toughness as well as creep/fatigue effect. MML theory’s influenced by mechanical and chemical reaction during sliding process. Self lubrication theory is influenced by the smearing of soft reinforcement phase on the contact surfaces during sliding process. Wear mechanism that occurred during dry siding wear of hybrid composite (multiple reinforcement composite consist of combination of hard and soft reinforcement) is combination of various mechanism and highly complex phenomenon.
References:
REFERENCES
1. Stachowiak GW. Wear: Materials, Mechanisms and Practice. John Wiley and Sons, Ltd. 2005: 2-3.
2. Hutchings IM. Tribology: Friction and Wear of Engineering Materials. Butterworth-Heinemann 1992:5-6.
3. Finkin EF. Speculations on the theory of adhesive wear. Wear 1972; 21:103-114.
4. Chawla N, Chawla KK. Metal Matrix Composites. Springer Science Business Media, Inc. 2006:337-8.
5. Archard HC. Contact and rubbing of flat surface. J. Appl. Phys. 1953; 24: 981-988.
6. Suh NP. The delamination theory of wear. Wear 1973; 25: 111-124.
7. Sin H, Saka N, Suh NP. Abrasive wear mechanisms and the grit size effect. Wear 1979; 55: 163-190.
8. 8.Khruschov MM, Babichev MA. Resistance to abrasive wear and the hardness of metals (in Russian), Dokl. Akad. Nauk SSSR 1953; 445- 448.
9. Rabinowicz E, Mutis A. Effect of abrasive particle size on wear. Wear 1965; 8: 381-390.
10. Zhang Z, Zhang L, Mai YM. Modeling steady wear of steel/Al2O3-Al particle reinforced composites system. Wear 1997; 211: 147-150.
11. Khruschov MM. Principle of abrasive wear. Wear 1974; 28: 69- 88.
12. Avient BWE, Gorddard J, Wilman H. An experimental study of friction and wear durin abrasion of metals, Proc. Roy. Soc. (London) 1960; Ser. A258, 159-180.
13. Avient BWE, Wilman H. New features of the abrasion process shown by soft metals; the nature of mechanical polishing, J. Applied Phys. 1962; 13: 521-526.
14. Mulhern TO, Samuels LE. The abrasion of metals: a model of the process. Wear 1962; 5: 478-498.
15. Larsen-Basse J. Influence of grit diameter and specimen size on wearduring sliding sliding abrasion. Wear 1968; 12: 35-53.
16. Moore MA, King FS. Abrasives wear of brittle solids. Wear 1980; 60: 123-140.
17. Zum Gahr KH. Microstructure and wear of materials, Elsevier, Amsterdam 1987, p.p.80-124, 351- 477.
18. Spurr RT. Temperatures reached during sliding. Wear 1976; 55: 259.
19. Miki H, Kobayashi S. An equation for the centre-line average roughness of material slide against abrasive paper. Wear 1980; 65: 47- 53.
20. Wang AG, Hutchings IM. The number of particle contacts in twobody abrasive wear of metals by coated abrasive papers. Wear 1989; 129: 23-35.
21. Spurr RT. The nature of contact during abrasion. Wear 1981; 67: 375-379.
22. Lin SJ, Liu KS. Effect of aging on abrasion rate in an Al---Zn---Mg--- SiC composite. Wear 1988; 121: 1- 14
23. Wang A, Rack HJ. Abrasive wear of silicon carbide particulate—and whisker-reinforced 7091 aluminum matrix composites. Wear 1991; 146: 337-348.
24. Lee HL, Lu WH, Chan SLI. Abrasive wear of powder metallurgy Al alloy 6061-SiC particle composites. Wear 1992; 159: 223-231.
25. Song WQ, Krauklis P, Mouritz AP, Bandyopadhyay S. The effect of thermal ageing on the abrasive wear behavior of age-hardening 2014 Al/SiC and 6061 Al/SiC composites. Wear 1995; 185: 125- 130.
26. Ahlatci H, Candan E, Iu HC. Abrasive wear behavior and mechanical properties of Al-Si/SiC composites. Wear 2004; 257: 625- 632.
27. Das S, Mondal DP, Sawla S, Ramakrishnan N. Synergic effect of reinforcement and heat treatment on the two body abrasive wear of an Al-Si alloy under varying loads and abrasive sizes. Wear 2008; 264: 47- 59.
28. Modi OP. Two-body abrasion of a cast Al-Cu (2014 Al) alloy-Al2O3 particle composite: influence of heat treatment and abrasion test parameters. Wear 2001; 248: 100- 111
29. Jahanmir S, Suh NP. Mechanics of subsurface void nucleation in delamination wear. Wear 1977a; 44: 17-38.
30. Argon AS. Formation of cavities from nondeformable second-phase particles in low temperature ductile fracture. Trans. ASME, Ser. H. J. Engng. Mater. Technol. 1976; 98: 60-68.
31. Saka N, Pamies-Teixeira JJ, Suh NP. Wear of two-phase metals. Wear 1977; 44: 77-86.
32. Alpas AT, Zhang J. Effect of SiC particulate reinforcement on the dry sliding wear of aluminium-silicon alloys (A356). Wear 1992; 155: 83- 104.
33. Wang DZ, Peng HX, Liu J, Yao CK. Wear behavior and microstructural changes of SiCw-Al-Al composite under unlubricated sliding friction. Wear 1995; 184: 187-192.
34. Venkataraman B, Sundarajan G .The sliding wear behaviour of AlSiC particulate composites-II, The characterization of subsurface deformation and correlation with wear behaviour. Acta Mater. 1996ab; 44: 451-460.
35. Heilmann P, Don J, Sun TC, Rigney DA, Glaeser WA. Sliding wear and transfer. Wear 1983; 91: 171-190.
36. Shivanath R,Sengupta PK, Eyre TS. Oxidative wear aluminium-silicon alloys. Br. Foundryman 1977; 70: 349-356.
37. Razavizadeh K, Eyre TS. Oxidative wear of aluminium alloy. Wear 1982; 79: 325-333.
38. Subramaniam C. On mechanical mixing during dry sliding of aluminium -12.3 wt. % silicon alloy against copper. Wear 1993; 161: 63-60.
39. Iwai Y, Yoneda H, Honda T. Sliding wear behavior of SiC whisker-reinforced aluminum composite. Wear 1995; 181: 594- 602.
40. Li XY, Tandon KN. Microstructural characterization of mechanically mixed layer and wear debris in sliding wear of an Al alloy and an Al based composite. Wear 2000; 245: 148-161.
41. Deuis RL, Subramaniam C, Yellup JM. Dry sliding wear of aluminium composite-a review. Composite Science and Technology 1997; 57: 415-435.
42. Rosenfield AR. A shear instability model of sliding wear. Wear 1987; 116: 319-328.
43. Bowden FP, Tabor D. The Friction and Lubrication of Solids, Vols I and II. Oxford University Press, Oxford 1964.
44. Liu YB, Lim SC, Ray S, Rohatgi PK. Friction and wear of aluminum-graphite composites: the smearing process of graphite during sliding. Wear 1992; 159: 201-205.
45. Alexeyex N, Jahanmir S. Mechanics of friction in selflubricating composite materials II: Deformation of the interfacial film. Wear 1993b; 166: 49-54.
46. Gibson PR, Clegg AJ, Das AA. Wear of cast Al-Si alloys containing graphite. Wear 1984; 95: 193-198.
47. Das S, Prasad SV, Ramachandran TR. Microstructure and wear of cast (Al-Si alloy) graphite composites. Wear 1989; 133:173-187.
48. Jha AK, Prasad SV, Upadhyaya GS. Sintered 6061 aluminum alloy-solid lubricant particle composites: sliding wear and mechanisms of lubrication. Wear 1989; 133: 163- 172.
49. Lin CB, Chang RJ, Weng WP. A study on process tribological behaviour of Al alloy/Gr. (p) composite. Wear 1998; 217: 167- 174.
50. Goto H, Uchijo K. Wear mechanism of Al-Si alloy impregnated graphite composite under dry sliding. Wear 2005; 259: 613-619.
51. Sannino AP, Rack HJ. (1995). Dry sliding wear of discontinuously reinforced aluminium composites: review and discussion. Wear 1995; 189(1-2): 1-19.
52. Riahi AR, Alpas AT. The role of tribo-layers on the sliding wear behavior of graphitic aluminium matrix composites. Wear 2001; 251: 1396-1407.
53. Fu HH, Han KS, Song JI. Wear properties of Saffil/Al, safil/Al2O3/Al and Saffil/SiC/Al hybrid metal matrix composites. Wear 2004; 256: 705-713.
54. Jun D L, Hui Y, Rong YS, Fang LW. Dry sliding friction and wear properties of Al2O3 and carbon short fibres reinforced Al-12Si alloy hybrid composites. Wear 2004; 257(9-10): 930-940
55. Hui LY, Jun D, Rong YS, Wei W. High temperature friction and wear behaviour of Al2O3 and/or carbon short fibre reinforced Al-12Si alloy composites. Wear 2004; 256(3-4): 275-285.
56. Basavarajappa S, Chandramohan G, Mahadevan A, Thangavelu M, Subramanian R, Gopalakrishnan P. Influence of sliding speed on the dry sliding wear behaviour and the subsurface deformation on hybrid metal matrix composite. Wear 2007; 262(7-8): 1007-1012.
57. Benal MM, Shivanand HK. Effects of reinforcement content and ageing duration on wear characteristics of Al (6061) based hybrid composites. Wear 2007; 262: 759-763.
58. Naplocha K, Granat K. Dry sliding wear of Al/Saffil/C hybrid metal matrix composites. Wear 2008; 265(11-12): 1734-1740.
59. Suresha S, Sridhara BK. Effect of addition of graghite particulates on the wear behaviour in aluminiumsilicon carbide-graphite composites. Materials and Design 2010; 31(4): 1804.
60. Suresha S, Sridhara BK. Effect of silicon carbide particulates on wear resistance of graphitic aluminium matrix composites. Materials and Design 2010; 31(9): 4470-4477.
61. Wang YQ, Afsar AM, Jang JH, Han KS, Song JI. Room temperature dry and lubricant wear behaviours of Al2O3f/SiCp/Al hybrid metal matrix composites. Wear 2010; 268(7-8): 863-870.
|