SiC颗粒增强铝基复合材料的摩擦磨损机制研究

SiC颗粒增强铝基复合材料是一种性能优异的高速摩擦材料,作为刹车材料必将在陆上运输领域得到广泛应用。但SiC颗粒增强铝基复合材料的摩擦磨损性能强烈地依赖于实验条件和制备工艺。综述了各种因素对SiC颗粒增强铝基复合材料摩擦磨损性能的影响,总结了SiC颗粒增强铝基复合材料摩擦磨损机制,并指出了SiC颗粒增强铝基复合材料需进一步深入研究的问题及新的研究方向。     

SiC和WS2颗粒协同改性铜/聚酰亚胺树脂基复合材料的摩擦磨损性能

采用粉末冶金法制备了总质量分数为20％SiC与WS2的铜/聚酰亚胺树脂基复合材料,WS2和SiC质量比分别为1:3,3:5,1:1,5:3,3:1,研究了固体润滑剂WS2与增强相SiC质量比对复合材料微观形貌和摩擦磨损性能的影响.结果表明:当WS2与SiC质量比为3:5时,复合材料中开始形成以WS2颗粒为核、SiC颗粒...     

快速凝固结合粉末冶金法制备SiC_p/AZ91复合材料的组织及性能

用快速凝固结合粉末冶金法制备了SiC颗粒增强镁合金基复合材料(SiCp/AZ91)棒材,研究了SiC颗粒含量对复合材料室温力学性能及显微组织的影响.结果表明:制备的复合材料棒材中SiC颗粒在基体中分布均匀,但仍存在局部颗粒团聚现象;随SiC颗粒含量的增加,复合材料的屈服强度、抗拉强度和断后伸长率均逐渐降低;热挤压过程中,镁、SiC和SiO2之间发生了界面反应,在界面生成Mg2Si等脆性相,影响了复合材料的界面性能.     

铺粉工艺对SiC 颗粒增强铝基表面复合材料性能的影响*

搅拌法制备SiC颗粒增强铝基复合材料时铺粉工艺对材料性能影响很大,影响SiC颗粒能否均匀地嵌入基体中。研究黏接剂、SiC颗粒粒径、颗粒铺粉厚度等对搅拌摩擦制备SiC颗粒增强铝基复合材料的影响。以焊缝宏观质量、SiC颗粒体积分数与硬度、基体组织及颗粒、复合材料不同深度维氏硬度、复合区面积(宏观)为表征参量对制备的复合材料进行表征,并得出最佳的铺粉工艺。结果表明:相比于α-氰基丙烯酸乙酯,聚乙烯醇作为黏接剂时,复合材料中SiC颗粒的分布更加均匀;嵌入基体的SiC颗粒体积分数随着SiC粉末粒径的增加而增加,而基体中SiC颗粒体积分数相同情况下,SiC颗粒的粒径越小对基体材料硬度的提高越明显;复合材料中SiC颗粒增强区面积会随着铺粉厚度的增加而增加,但增加铺粉厚度会使得SiC颗粒增强区硬度、体积分数的变化梯度增加。     

Al_2O_3连续增强铝基复合材料的干摩擦磨损特性

通过摩擦磨损试验对比研究了含质量分数18%SiC颗粒和不含SiC颗粒的Al2O3连续增强铝基复合材料与NAO(无石棉有机材料)配副的干滑动摩擦磨损行为。结果表明:复合材料在较低的滑动速度(0.628m·s-1)下,最大启动摩擦因数随正压力的增大而降低;在较高的滑动速度(2.512m·s-1)下,最大启动摩擦因数随正压力的增大呈先减小后增大的趋势;正压力一定时,最大启动摩擦因数随滑动速度的增大先减小后增大;含SiC的Al2O3连续增强铝基复合材料比不含SiC的Al2O3连续增强铝基复合材料具有更高的摩擦因数和更好的耐磨性。     

消失模铸渗法制备SiC颗粒增强钢基表面复合材料

通过涂覆预制块的预置方法,利用消失模(V-EP)铸渗工艺制备了SiC颗粒增强钢基表面复合材料,着重研究碳化硅粒径对表面复合效果的影响.结果表明:碳化硅颗粒粒径在600～850 μm时,制备的复合材料表面复合效果好,铸渗复合层厚度可达4 mm左右,表面较平整;碳化硅颗粒粒径对SiC/钢复合材料表面质量有很大的影响,随着SiC颗粒粒径的增加,复合材料铸渗层的表面质量呈下降趋势.     

电铸制备SiC颗粒增强镍基复合材料的工艺与性能

采用电铸技术(氨基磺酸镍电铸液)成功制备了SiC颗粒增强镍基复合材料;用Leica Qwin图形分析软件和显微硬度计分析了电铸工艺参数对SiC颗粒增强镍基复合材料中SiC颗粒含量以及SiC含量对该复合材料显微硬度的影响;用场发射扫描电镜分析了复合材料的截面形貌和SiC分布.结果表明:在SiC加入量50 g·L-1、电流密度3 A·dm-2和磁力搅拌强度1.5次/min条件下,复合材料中SiC颗粒体积分数达到最高值27%,其显微硬度值也最高,为710 HV.     

SiC颗粒增强镁-锌-锆基复合材料的阻尼性能

采用热压烧结法制备了三种不同成分的SiC颗粒增强镁-锌-锆基复合材料,使用LMR-1型低频力学弛豫谱测试系统研究了铸态镁-锌-锆合金及热压烧结SiCp/镁-锌-锆基复合材料的阻尼性能随频率和温度的变化关系.结果表明:SiC颗粒的加入使复合材料的阻尼性能比基体合金有显著提高;另外随着合金中锌含量的增加,复合材料的内耗值不断下降;在频率为3×10-3～7Hz范围内,基体合金及复合材料的内耗值均随着频率的增加先快速减小随后又逐渐增大;在本试验条件下SiCp/Mg-0.93%Zn-0.70%Zr基复合材料的内耗值最大,该复合材料在50～100℃的温度范围内出现弛豫内耗峰.     

搅拌摩擦加工工艺制备ZrO_2颗粒增强镁基复合材料的组织与力学性能

利用4道次搅拌摩擦加工(FSP)工艺,分别将粒径为20nm的单斜晶ZrO_2(M-ZrO_2)颗粒和40nm的正方晶ZrO_2(T-ZrO_2)颗粒添加到AZ31镁合金中制备了ZrO_2颗粒增强镁基复合材料,研究了复合材料的显微组织与力学性能,并与无强化颗粒FSP镁合金的进行了对比。结果表明:M-ZrO_2颗粒和T-ZrO_2颗粒增强镁基复合材料的晶粒尺寸分别约为6μm和2μm;两种ZrO_2颗粒均弥散分布于复合材料中,且均未与基体反应生成新物相;ZrO_2颗粒可有效提高镁合金的硬度、屈服强度和抗拉强度,且T-ZrO_2颗粒的强化效果更好;无强化颗粒FSP镁合金与M-ZrO_2颗粒增强复合材料拉伸断口均具有混合断裂特征,前者的韧性断裂特征较明显,后者的脆性断裂特征较明显。     

SiC颗粒增强铝基复合材料的摩擦磨损性能

制备了不同粒度和含量siC的铝基复合材料,与santana2000轿车用HFM605型非金属摩擦片材料配成摩擦副,于不同压力和速度条件下在MM-200型摩擦磨损试验机上进行干摩擦试验,研究了其摩擦磨损性能。结果表明:摩擦因数随摩擦压力的增大而下降;比较而言,在高速高压时摩擦因数最低;复合材料中SiC粒度和含量对摩擦因数影响不大;随着siC粒度减小、含量增大,复合材料的耐磨性能逐渐提高;热处理可以明显提高复合材料的摩擦因数和耐磨性能。     

Effect of SiC Particle Size on Wear Properties of Al2O3·SiO2/SiC/Mg Hybrid Metal Matrix Composites

The aim of this study was to investigate the effect of SiC particle size on the wear properties of magnesium-based hybrid metal matrix composites (MMCs) reinforced with Saffil short fibers and SiC particles. Hybrid MMCs with different SiC particle sizes of 1, 7, and 20 μm, respectively, were fabricated by the squeeze infiltration process. The volume fractions of Saffil short fibers and SiC particles in the hybrid composites were 15 and 5%, respectively. Wear tests were carried out using a ball-on-disk against a steel ball under the dry sliding condition. The test results showed that the composite with large-sized SiC particles had an improved wear resistance compared with the smaller sized particles.     

Tribology at high-velocity impact

The tribological events taking place when a high-velocity projectile hits a SiC particulate reinforced AA 5083 composite material was examined under real conditions. The samples were cast in a disc shape by squeeze casting method. Different volume fractions of SiC particles were used. They were solidified under 180 MPa in a steel mould with a 650–700 °C temperature range. SiC particles with the size of 250–500 μm, and 30% and 45% in volume fraction were incorporated into the matrix material. The composites were machined to ensure a smooth surface and to obtain samples without burrs. The samples had a diameter and thickness of 140 and 20 mm, respectively. The terminal ballistic tests were carried out in an army zone under standard test conditions. An AP 7.62 mm armour piercing projectile with a speed of 710 m/s was used for testing the composite.The frictional characteristics and wear mechanisms caused by high-velocity impacts to the composite were determined by SE microscopy studies. The evaluations of the tribological events on both the hole and projectile tip surfaces resulting from high-velocity friction were carried on. As the projectile moved thorough the composite, some material broke from the matrix body and conglomerated along the path followed by the missile. Then these conglomerated blocks yielded and slided along the hole surface. There were also scratching and local melting on the hole surface. Similarly, some ploughing took place on the hole, some SiC particles were removed from the matrix body by the friction effect of projectile and these particles were conglomareted on the tip surface of the projectile. Thus, the nature of wear mechanism on the projectile surface was predominantly abrasive while those of the friction surfaces of the composites were predominantly abrasion and melt wear.     

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.     

Investigation into sliding wear performance of zinc-based alloy reinforced with SiC particles in dry and lubricated conditions

The objective of the present investigation was to assess the influence of SiC particle dispersion in the alloy matrix, applied load, and the presence of oil and oil plus graphite lubricants on the wear behaviour of a zinc-based alloy. Sliding wear performance of the zinc-based alloy and its composite containing SiC particles has been investigated in dry and lubricated conditions. Base oil or mixtures of the base oil with different percentages of graphite were used for creating the lubricated conditions. Results show a large improvement in wear resistance of the zinc-based alloy after reinforcement with SiC particles. The lubrication improved the wear resistance and friction behaviour of both the reinforced and base alloys. It was also observed that there exists an optimum concentration of graphite particles in the lubricant mixture that leads to the best wear performance. The composite experienced higher frictional heating and friction coefficient than the matrix alloy in all the cases except oil lubricated conditions; a mixed trend was noticed in the latter case. The wear rate and frictional heating increased with load while friction coefficient was affected in an opposite manner. Test duration influenced the frictional heating and friction coefficient of the samples in a mixed manner.Examination of worn surfaces revealed a change of predominating wear mechanisms from severe ploughing and/or abrasive wear for base alloy to delamination wear for the reinforced material under dry sliding conditions. The presence of the lubricant increased the contribution of adhesive wear component while reducing the severity of abrasion. This was attributed to the generation of more stable lubricant films on the contacting surfaces. Cross-sections of worn surfaces indicated substantial wear-induced plastic deformation, thereby suggesting adhesive wear to be a predominant wear mechanism in this study. The debris particles revealed deformed flakes and machining chips signifying the involvement of adhesion and abrasion modes of wear respectively.     

载荷对激光选区烧结Cf/SiC复合材料摩擦磨损性能的影响

通过激光选区烧结技术和液相渗硅工艺制备了碳纤维增强碳化硅（Cf/SiC）复合材料。试样组织由C、SiC和Si三相组成,其密度和弯曲强度分别为2.89±0.01 g/cm3和237±9.8 MPa。采用UMT TriboLab多功能摩擦磨损试验机研究了Cf/SiC复合材料在不同载荷(10 N, 30 N, 50 N和70 N)条件下的摩擦学特性。研究结果表明：载荷较小(10 N)时,Cf/SiC复合材料的磨损由微凸起和SiC硬质点造成,磨损机制为磨粒磨损;载荷为30 N时,复合材料的摩擦磨损综合性能最好,其平均摩擦因数为0.564,磨损率低(5.24×10-7 cm3/（N·m）),主要磨损机制为犁削形成的磨粒磨损和黏结磨损。载荷增大到70N时,材料磨损严重,磨粒脱落形成凹坑,产生裂纹,其磨损率(8.68×10-7 cm3/（N·m）)高,磨损机制主要为脆性剥落。     

Heat Treated NiP–SiC Composite Coatings: Elaboration and Tribocorrosion Behaviour in NaCl Solution

Tribocorrosion behaviour of heat-treated NiP and NiP–SiC composite coatings was investigated in a 0.6 M NaCl solution. The tribocorrosion tests were performed in a linear sliding tribometer with an electrochemical cell interface. It was analyzed the influence of SiC particles dispersion in the NiP matrix on current density developed, on coefficient of friction and on wear volume loss. The results showed that NiP–SiC composite coatings had a lower wear volume loss compared to NiP coatings. However, the incorporation of SiC particles into the metallic matrix affects the current density developed by the system during the tribocorrosion test. It was verified that not only the volume of co-deposited particles (SiC vol.%) but also the number of SiC particles per coating area unit (and consequently the SiC particles size) have made influence on the tribocorrosion behaviour of NiP–SiC composite coatings.     

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).     

改性纳米SiC粉体强化球墨铸铁的耐磨损性能

采用改性纳米SiC粉体对球墨铸铁进行了强韧化处理,研究了不同的纳米SiC粉体加入量对球墨铸铁的微观组织、力学性能以及耐磨损性能的影响。结果表明,经改性纳米SiC粉体强韧化处理后,球墨铸铁中的石墨球尺寸减小,圆整度提高,铁素体含量增多,球墨铸铁的韧性和耐磨损性能提高。当粉体加入量为0.1%（质量分数）时,其延伸率和冲击功分别增加了19%和194%。耐磨损性能提高的原因是石墨球形态的改善和基体组织韧性的提高。     

纳米和微米La2O3颗粒增强镍基复合镀层的摩擦磨损性能

用复合电沉积工艺制备了纳米和微米La2O3颗粒增强镍基复合镀层，在销盘式滑动磨损试验机上考察了复合镀层在干摩擦条件下的摩擦磨损性能，用扫描电子显微镜分析了其磨损机理。结果表明：在干摩擦条件下，纳米La2O3颗粒增强复合镀层的摩擦磨损性能明显优于微米La2O3颗粒增强复合镀层；纳米La2O3增强镍基复合镀层的磨损主要表现为轻微磨粒磨损特征，而微米La2O3增强镍基复合镀层的磨损机制为剥层磨损和磨粒磨损。