Dry three-body abrasive wear behavior of WC reinforced iron matrix surface composites produced by V-EPC infiltration casting process

This paper fabricated tungsten carbide (WC) particles reinforced iron matrix surface composites on gray cast iron substrate using vacuum evaporative pattern casting (V-EPC) infiltration process, investigated dry three-body abrasive wear resistance of the composites containing different volume fractions of WC particles, comparing with a high chromium cast iron. The fabricated composites contained WC particles of 5, 10, 19, 27, 36, and 52 vol.%, respectively. The results in abrasive wear tests showed that, with the increase in the volume fraction of WC particles, the wear resistance of the composites first increased until reached the maximum when the volume fraction of WC was 27%, then decreased, and was 1.5–5.2 times higher than that of the high chromium cast iron. The changes of the wear resistance of the composites with the volume fraction of WC particles and the mode of material removal in dry three-body abrasive wear condition were analyzed.     

High stress abrasive wear behaviour of aluminium hard particle composites: Effect of experimental parameters, particle size and volume fraction

High stress abrasive wear behaviour of aluminium alloy (ADC-12)–SiC particle reinforced composites has been studied as a function of applied load, reinforcement size and volume fraction, and has been compared with that of the matrix alloy. Two different size ranges (25–50 and 50–80 μm) of SiC particles have been used for synthesizing ADC-12–SiC composite. The volume fraction of SiC particles has been varied in the ranges from 5 to 15 wt%. It has been noted that the abrasive wear rate of the alloy reduced considerably due to addition of SiC particle and the wear rate of composite decreases linearly with increase in SiC content. It has also been noted that the wear resistance of composite varies inversely with square of the reinforcement size. The wear rate of the alloy and composite has been found to be a linear function of applied load but invariant to the abrasive size; at critical abrasive size, transition in wear behaviour is noted. This has been explained through analytically derived equations and wear–surface examination.     

Abrasive wear behaviour of B4C particle reinforced Al2024 MMCs

In this study, the effects of volume fraction and particle size of boron carbide on the abrasive wear properties of B₄C particle reinforced aluminium alloy composites have been studied. For this purpose, a block-on-disc abrasion test apparatus was utilized where the samples slid against the abrasive suspension mixture at room conditions. The volume loss, specific wear rate and roughness of the samples have been evaluated. The effects of sliding time, particle content and particle size of B₄C particles on the abrasive wear properties of the composites have been investigated. The dominant wear mechanisms were identified using scanning electron microscopy. The results showed that the specific wear rate of composites decreased with increasing particle volume fraction. Furthermore, the specific wear rate decreased with increasing the size of particle for the composites containing the same amount of B₄C. Hence, it is deduced that aluminium alloy composites reinforced with larger B₄C particles are more effective against the abrasive suspension mixture than those reinforced with smaller B₄C particles.     

WC颗粒增强铁基表面复合材料的三体磨料磨损性能研究

设计、制备了一台三体磨料磨损实验机，对该实验机进行了重现性实验。以高铬铸铁为标样，利用该磨损实验机分别考察了WC颗粒体积分数、载荷与表面复合材料相对耐磨性能之间的关系。实验结果表明：本实验机的测试性能是可靠的；复合材料的三体磨料磨损性能与高铬铸铁标样相比有较明显的提高，在同一载荷下．复合材料的相对耐磨性能随着WC颗粒体积分数的增大呈先升高后降低的变化规律，WC颗粒体积分数为27％的复合材料相对耐磨性最高，达到高铬铸铁的5．12倍；而对于同一种复合材料，随着载荷的增大，其相对耐磨性呈增加趋势，其中WC颗粒体积分数为27％的复合材料增加最为明显；复合材料的三体磨料磨损机理为WC对周围组织的屏蔽作用，失效方式为WC颗粒因疲劳而片状剥落。     

Effect of the Graphite Content on the Tribological Behavior of Al/Gr and Al/30SiC/Gr Composites Processed by In Situ Powder Metallurgy (IPM) Method

The influence of graphite content on the dry sliding wear characteristics of Al6061/Gr composites along with Al6061/30SiC/Gr hybrid composites has been assessed using a pin-on-disc wear test. The composites with different volume fraction of graphite particles up to 13% were processed by in situ powder metallurgy (IPM) technique. The porosity and hardness of the resultant composites were also examined. It was found that an increase in the graphite content reduced the porosity, hardness, and friction coefficient of both types of composites. The hybrid composites were more porous and exhibited higher hardness and lower coefficient of friction at identical graphite contents. The increased graphite content in the range of 0–13 vol.% resulted in increased wear rate of Al/Gr composites. The Al/30SiC composite exhibited a lower wear rate as compared with the base alloy and graphite addition up to 9 vol.% improved the wear resistance of these hybrid composites. However, more graphite particles addition resulted in increased wear rate. SEM micrographs revealed that the wear mechanism was changed from mostly adhesive in the base alloy sample (Al/0Gr) to the prominently abrasive and delamination wear for Al/Gr and Al/SiC/Gr/composites.     

Desirability based multiobjective optimisation of abrasive wear and frictional behaviour of aluminium (Al/3.25Cu/8.5Si)/fly ash composites

Aluminium alloy (Al/3.25Cu/8.5Si) composites reinforced with fly ash particles of three different size ranges (53–75?μm, 75–103?μm and 103–125?μm) in 3, 6 and 9 wt-% were fabricated using liquid metallurgy technique. Pin on disc abrasive wear tests were carried against the disc surface fixed with SiC emery paper (120 grades). A mathematical model was developed to predict the abrasive wear and coefficient of friction of the composites. Analysis of variance technique was used to check the validity of the developed model. Composites reinforced with coarse fly ash particles exhibited better abrasive wear resistance than those reinforced with fine fly ash particles. Abrasive wear in composites with fine fly ash particles is a combination of adhesive wear and abrasive wear. Larger fly ash particles present in composites gets fractured into fine particles and entrapped between the composite pin and the disc, thereby decreasing the wear rate. Worn surfaces of the pins were then analysed using scanning electron microscopy to study the wear mechanisms of the composites. The abrasive wear was optimised using desirability based multiobjective optimisation technique.     

Comparison on abrasive wear of SiCrFe, CrFeC and Al2O3 reinforced Al2024 MMCs

The effects of volume fraction and size of SiCrFe, CrFeC, and Al₂O₃ particulates on the abrasive wear rate of compo-casted Al2024 metal matrix composites (MMCs) were studied. The process variables like the stirring speed, position and the diameter of the stirrer have affected the diffusion between particulates and matrix.The abrasive wear rate was decreased by the increase in particulate volume fraction of SiCrFe and CrFeC intermetallic reinforced composites over 80 grade SiC abrasive paper. The wear rates of the all composites decreased with aging treatment, and the best result was seen for the composite having a hybrite structure as SiCrFe and CrFeC particulates together. Nevertheless, the fabrication of composites containing soft particles as copper favors a reduction in the friction coefficient.     

Wear and abrasion of cast Al-Alumina particle composites

Wear rates for cast aluminium and Al-Si alloys containing up to 5 wt.% γ-Al₂O₃ particles (100 μm size) were determined under conditions of adhesive wear and abrasive wear against a hardened steel disc and an alumina abrasive cloth sheet respectively. The adhesive wear rate of aluminium containing 5 wt.% A1₂O₃ dispersions is similar to that of Al-11.8Si eutectic alloy and slightly higher than that of A1-16Si hypereutectic alloy. Al-3wt. %Al₂O₃ and Al-5wt.%Al₂O₃ composites perform better than Al-11.8Si and Al-16Si hypereutectic alloys under abrasive wear conditions. Al-11.8Si and Al-16Si alloys have a lower abrasive wear resistance than pure aluminium. The results indicate that Al₂O₃ particles can be used as a substitute for silicon as the hard dispersed phase in aluminium for wear-resistant and abrasion-resistant applications.     

Dry sliding wear of fly ash particle reinforced A356 Al composites

In the present study aluminium alloy (A356) composites containing 6 and 12 vol. % of fly ash particles have been fabricated. The dry sliding wear behaviour of unreinforced alloy and composites are studied using Pin-On-Disc machine at a load of 10, 20, 50, 65 and 80 N at a constant sliding velocity of 1 m/s. Results show that the dry sliding wear resistance of Al-fly ash composite is almost similar to that of Al₂O₃ and SiC reinforced Al-alloy. Composites exhibit better wear resistance compared to unreinforced alloy up to a load of 80 N. Fly ash particle size and its volume fraction significantly affect the wear and friction properties of composites. Microscopic examination of the worn surfaces, subsurfaces and debris has been done. At high loads (>50 N), where fly ash particles act as load bearing constituents, the wear resistance of A356 Al alloy reinforced with narrow size range (53–106 μm) fly ash particles were superior to that of the composite having the same volume fraction of particles in the wide size range (0.5–400 μm).     

Effect of reinforcement size and volume fraction on the abrasive wear behaviour of AA7075 Al/SiCp P/M composites—A statistical analysis

In the present study, a new mathematical model was developed to predict the abrasive wear rate of AA7075 aluminum alloy matrix composites reinforced with SiC particles. Five factors, five levels, central composite, rotable design matrix was used to optimise the required number of experiments. The model was developed by response surface method. Analysis of variance technique was applied to check the validity of the model. Student's t-test was utilised to find out the significant factors. The effect of volume percentage of reinforcement, reinforcement size, applied load, sliding speed and abrasive size on abrasive wear behaviour was analysed in detail.     

Wear Behavior of Dual Particle Size (DPS) Zircon Sand Reinforced Aluminum Alloy

The present investigation aims to find the combined effect of coarse and fine size particle reinforcement of zircon sand in aluminum alloy LM13 on the wear behavior. The composites are fabricated by varying the reinforcement of fine and coarse size zircon sand particles and compared with the single size reinforcement. Coarse and fine particle zircon sand of 106?C125 and 20?C32-??m size, respectively, are used in this study. The wear test was carried out on pin-on-disc machine. Microhardness measurement was done for developed composites. Wear track and debris are analyzed by SEM to study the wear mechanism. Line profile and EDS analysis is also done to validate the microstructural results. Study reveals that a combination of 3?% fine and 12?% coarse particle reinforced composite exhibits better wear resistance while 3?% coarse and 12?% fine particle reinforcement decreases the wear resistance. It is also observed that zircon sand particles provide effective nucleation site for the eutectic silicon. Microstructural examination shows globular and finely distributed eutectic silicon in the vicinity of the reinforced particles.     

Abrasive wear behaviour of sintered composite austenitic stainless steels having γ-Fe and M23C6 phases

Abstract

Using powder metallurgy, composites of austenitic stainless steel were produced along with unreinforced stainless steel mixed with titanium, cobalt and molybdenum particles. Wear resistance of the materials was measured by a two body pin on disc wear tester. SiC abrasive papers of 80 and 220 mesh sizes were used as abrasive media. Wear tests were performed under loads of 10, 20 and 30 N at room temperature. The abrasive wear measurements showed that the softer, unreinforced austenitic stainless steel exhibited higher mass loss than the composites. Furthermore, the abrasive wear resistance of the reinforced austenitic stainless steel composites increased with increasing FeTi, FeMo, or Co volume content. In addition, the wear rate against the 80 grade SiC abrasive paper increased more than against the 220 grade SiC abrasive paper.     

Tribological performance of A206 aluminum alloy containing silica sand particles

The dry-sliding tribological behavior of A206 aluminum alloy containing silica sand was investigated using a three pin-on-disk tribometer against an SAE 1045 steel counterface. The worn surfaces of the pins were then analyzed by optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS). The test results showed that the addition of silica sand particles decreased the friction coefficient of Mg modified A206 alloy. The wear rate of the composites increased with increases in the applied pressure from 0.35 to1.75 MPa and with increases in the silica sand content from 0% to 13%. The wear rate variation with the applied pressure is attributed to the shift in the dominant wear mechanisms from oxidation and mild abrasive wear at applied pressures at and below 0.35 MPa to delamination accompanied by severe abrasive wear at applied pressure levels above 0.35 MPa. The high wear rate may be as a result of an overall decrease of the fracture toughness of the composites containing silica particles. The temperature near the counterface surface increased with increases in both silica content and the applied pressure due to the lower thermal conductivity of silica sand and greater abrasion that occurs at higher silica contents. A T6 heat treatment did not significantly decrease the friction coefficient or the wear rate of either the A206 matrix alloys or the composite containing silica sand.     

Dry Sliding Wear Behavior of Palmyra Shell Ash–Reinforced Aluminum Matrix (AlSi10Mg) Composites

High strength, light weight, ease of fabrication, excellent castability, and good wear resistance make aluminum alloy composites suitable for commercial applications. In this work, a silica-rich ash particle (palmyra shell ash) was reinforced with aluminum alloy (AlSi10Mg) composites and its mechanical and tribological properties were studied. The aluminum alloy was reinforced with 3, 6, and 9 wt% of palmyra shell ash particles, and its dry sliding wear behavior was studied using a pin-on-disc machine under different loading conditions. The result shows that the dry sliding wear resistance of Al–palmyra shell ash composites was almost similar to that of fly ash– and rice husk ash–reinforced Al-alloy composites and these composites exhibit better wear resistance compared to unreinforced alloy. The palmyra shell ash particle weight fraction significantly affects the wear and friction properties of the composites. Scanning electron microscopic examination of the worn surface reveals that at various loads palmyra shell ash particles act as load-bearing constituents and the wear resistance of the reinforced palmyra shell ash with a size range of 1–50 µm was superior to that of unreinforced alloy. Mechanical properties (hardness and tensile strength) were also studied and it was observed that the reinforced Al-alloy showed a significant increase in mechanical properties.     

Study of Non-lubricated Wear of the Al–Si Alloy Composite Reinforced with Different Ratios of Coarse and Fine Size Zircon Sand Particles at Different Ambient Temperatures

In the present work, a detailed study of ceramic reinforcement of different size ranges in the matrix of LM13 alloy on the friction and wear behavior has been carried out. For this purpose, LM13/Zr composite containing 10 wt% zircon sand particles of different size ranges using stir casting process has been developed. Zircon sand particles were incorporated in two ways: firstly as single size reinforcement and secondly dual size reinforcement. Durability of the composites was tested by finding the wear rate of the composite against the steel disk by pin-on-disk method. Addition of zircon sand particles in the LM13 alloy improves the hardness of the composite as well as wear resistance. Wear rate of the developed composites was tested under different test conditions by varying the applied load and ambient temperatures. Wear rate of the composite changes significantly at different ambient temperatures. SEM analysis of the worn surfaces was done to know the operative wear mechanism.     

Abrasive wear characteristics of a zinc-based alloy and zinc-alloy/SiC composite

An attempt has been made in this investigation to assess the contribution of various parameters towards governing the abrasive wear response of a zinc-based alloy under the conditions of varying applied loads and sliding distances. The factors whose contribution has been examined include deterioration in the cutting efficiency of the abrasive medium, role played by the SiC particles (dispersed in the alloy matrix) in terms of their degradation and resistance offered by them against the destructive action of the abrasive, subsurface hardening of the matrix and such other related aspects. Four types of abrasion tests were conducted on the samples to achieve the goal. The (abrasion) tests involved the use of (i) fresh as well as preworn surfaces of the samples and (ii) fresh and degraded abrasive media in four different combinations.The study suggests that the mentioned factors contribute to a varying degree towards controlling the (high-stress) abrasive wear behaviour of the specimens. However, degradation in the cutting efficiency of the abrasive medium (through capping, clogging, attrition and shelling) dominates over the influence of other parameters such as abrasion induced subsurface hardening of the matrix. Reinforcement of the SiC particles in the alloy matrix offered improved wear resistance (inverse of wear rate) under less severe conditions such as at low applied loads, wherein the dispersoid (SiC) particles could be retained by the matrix due to low cutting depths made by the abrasive particles. The dispersoid particles deteriorated the wear response of the matrix under more severe conditions of abrasion, such as at high loads, because of larger cutting depths causing fracturing and partial removal of the reinforcement (SiC) particles. The observed wear response of the samples has further been substantiated through the characteristics of wear surfaces, debris particles and abrasive medium after testing the matrix alloy and composite in a typical test condition expected to affect the abrasive medium and test specimens to the largest extent.     

The abrasive wear resistance of TIC and (Ti,W)C-reinforced Fe–17Mn austenitic steel matrix composites

Pin-on-disc dry sliding wear tests have been carried out to study the wear behaviour of 10 vol% TiC and (Ti,W)C-reinforced Fe–17Mn austenitic steel matrix composites. The composites have been synthesized in situ by means of conventional melting and casting route. It has been observed that the abrasive wear resistance of the composites is higher than that of their unreinforced Fe–17Mn austenitic steel. Compared with the TiC-reinforced composite, the abrasive wear resistance of the (Ti,W)C-reinforced composite is better. The abrasive wear resistance and coefficient of friction of both reinforced and unreinforced materials decrease as the load increases.     

Effect of carbide size on the abrasion of cobalt-base powder metallurgy alloys

A study of the effect of carbide size on the abrasion resistance of two cobalt-base powder metallurgy alloys, alloys 6 and 19, was conducted using low stress abrasion with a relatively hard abrasive, A1₂O₃. Specimens of each alloy were produced with different carbide sizes but with a constant carbide volume fraction. The wear test results show a monotonie decrease in wear rate with increasing carbide size.Scanning electron microscopy of the worn surfaces and of wear debris particles shows that the primary material removal mechanism is micromachining. Small carbides provide little resistance to micromachining because of the fact that many of them are contained entirely in the volume of micromachining chips. The large carbides must be directly cut by the abrasive particles. Other less frequently observed material removal mechanisms included direct carbide pull-out and the formation of large pits in fine carbide specimens. These processes are considered secondary in the present work, but they may have greater importance in wear by relatively soft abrasives which do not cut chips from the carbide phase of these alloys. Some indication of this is provided by limited studies using a relatively soft abrasive, rounded quartz.     

共沉淀法制备纳米Al2O3强化铜基复合材料微动磨损研究

采用共沉淀法制备了纳米Al2O3／Cu基复合材料,研究了不同Al2O3含量对铜基复合材料摩擦磨损性能的影响。结果表明,复合材料的耐磨性能明显优于基体材料,随着Al2O3含量的增加,复合材料的耐磨性能先升高后下降,以Al2O3含量2％为最佳,相对耐磨性为3．13。纯铜的磨损表现为粘着磨损,而复合材料则逐渐转变为磨粒磨损,并伴有一定的氧化磨损。     

Effect of indenter geometry and relationship between abrasive wear and hardness in early stage of repetitive sliding

This paper deals with the abrasive wear of 5xxx aluminium alloys, which is a major problem in industrial applications. First, the influence of work hardening on abrasive wear resistance is investigated. A work hardened and annealed aluminium alloy is subjected to repeated scratch test using a sphere/plane configuration. It is shown that the work hardening increases the abrasive wear resistance in early stage of repetitive sliding. In the second part, the influence of the geometry indenter on abrasive wear is investigated. Repeated scratch tests with conical indenter were carried out on the same aluminium alloys. Scratch test using a conical indenter was shown that work hardening treatment (H24) on the 5xxx aluminium alloy does not improve wear resistance. Moreover, the conical indenter induces greater wear than the spherical indenter in repetitive sliding with few number cycles (10 cycles). An accurate interpretation of these phenomena is then proposed.