压力对碳纳米管-银-石墨复合材料接触电压降的影响

采用粉末冶金法制备碳纳米管-银-石墨复合材料电接触材料,在带电状态下（10A／cm^2）,研究了压力对碳纳米管-银-石墨复合材料接触电压降的影响,结果表明：当压力较小时（10N／cm^2,5N／cm^2）,由于电刷的跳动产生火花,导致复合材料接触电压降较大;随压力增加,复合材料电刷和换向器的实际接触面积增大,接触电阻减小,电刷的接触电压降下降;由于碳纳米管的研磨作用,阻止了润滑膜随磨损时间延长而增厚,使电刷的接触电压降维持在一个较稳定的数值上。     

碳纳米管增强铝基复合材料的制备及摩擦磨损性能

采用粉末冶金常压烧结与高温模压和热挤压相结合的工艺制备了碳纳米管增强铝基复合材料,以探索复合材料的低成本制备技术。采用扫描电镜、万能材料试验机和摩擦磨损试验机研究了碳纳米管的添加量对复合材料力学性能和摩擦磨损性能的影响。结果表明,随着碳纳米管含量的增加（质量分数0～2％）,复合材料的硬度逐渐升高,抗拉强度先升高后下降。当碳纳米管含量为1．5％时抗拉强度达370 MPa,硬度和抗拉强度分别比纯铝提高了433％和236％。当碳纳米管含量为2％时,复合材料的摩擦因数和磨损量分别比纯铝降低了63％和14％。     

成分变化对铜-二硫化钼-石墨复合材料电磨损性能的影响

采用粉末冶金法在H。保护气氛下制备铜-二硫化钼一石墨复合材料,对其进行物相分析,并通过改变材料中Mo岛与石墨的含量,研究成分变化对复合材料电磨损性能的影响。结果表明：石墨在烧结过程中不参与反应,而MoS2与基体反应生成新相。随着复合材料中MoS2含量的增加和石墨含量的降低,电刷与换向器之间的接触电压降上升,摩擦系数增大,石墨含量最低时磨损量值最大并且出现火花磨损现象。     

颗粒级配对SiCp／Al复合材料摩擦磨损性能的影响

采用销-盘摩擦磨损试验机,考察了高体积分数SiCp/Al复合材料中颗粒尺寸及颗粒级配等组织因素对材料干摩擦磨损性能的影响.通过磨损表面的SEM形貌分析,研究了复合材料的磨损机理.结果表明,与灰铸铁配副时,材料的摩擦系数与磨损率明显依赖于碳化硅颗粒尺寸,二者均随颗粒尺寸的增大而先降低后增大.采用颗粒级配方法能明显改善复合材料的干摩擦磨损性能.粗细颗粒问的级配具有相互强化的作用,有利于降低摩擦系数和磨损率,并使其趋于稳定.复合材料的磨损以对偶件材料的转移和犁沟为特征.     

球形石墨增强银-石墨复合材料的摩擦学行为（英文）

采用粉末冶金技术分别制备球形石墨(SG)和鳞片石墨(FG)增强的银-石墨复合材料。并用销-盘式摩擦磨损仪在大气环境和3.0N的载荷下研究石墨形貌对银-石墨复合材料(Ag-SG和Ag-FG)摩擦学行为的影响。结果显示,Ag-FG的最低磨损率为3.5×10^-5mm³/(N·m),而Ag-SG的最低磨损率比Ag-FG低一个数量级,为1.6×10^-6mm³/(N·m)。Ag-SG和Ag-FG显著不同的摩擦学行为与亚表面裂纹的形成有关。在摩擦过程中,片状石墨的边缘容易发生应力集中,导致Ag-FG亚表面产生裂纹和严重的剥层磨损。然而,在Ag-SG中,球形石墨能有效抑制裂纹的萌生和扩展,从而使银-石墨复合材料具有优异的耐磨性能。     

纤维取向对复合材料摩擦磨损性能的影响

利用挤压铸造法制备了Al2O3f/ZL109短纤维筒形复合材料,在转速675 r/min、载荷100N条件下,对复合材料的纤维平行取向和纤维垂直取向磨损表面各进行了4组样品的试验,根据试验结果绘出纤维取向及体积分数对复合材料磨损性能影响的曲线图.结果表明,该复合材料纤维垂直取向比纤维平行取向耐磨,即纤维垂直取向有利于复合材料耐磨性能的提高.     

石墨-AZ91镁基复合材料及其摩擦磨损性能的研究

研究了不同石墨颗粒含量对AZ91镁合金基复合材料摩擦磨损性能的影响。结果表明：在所研究的范围内，复合材料的摩擦磨损特性明显优于基体合金；随着石墨颗粒含量从5％增加到20％，镁合金基复合材料的耐磨性得到明显的改善，磨损质量损失与摩擦系数都降低到较低水平。在不同磨损阶段，对应着不同磨损机制。随着磨损过程的进行，在磨损试样表面逐渐形成一层连续黑色润滑膜，这层润滑膜有效隔离两摩擦副的直接接触，有效地延迟了镁合金基复合材料由轻微磨损向严重磨损的转变过程。     

碳-铜基复合材料机械摩擦磨损性能研究

利用扫描电镜、金相显微镜等测试手段对面碳－铜复合材料几种组织状态下的机械摩擦磨损性能进行了研究。结果表明,复合材料具有合理的组织结构,可明显改善材料摩擦磨损性能,复合材料磨损性能随材料成形方向不同也有差异。     

银-石墨烯复合材料的滑动摩擦磨损性能

采用球磨混粉、冷等静压和真空烧结的工艺流程制备了含0.5%~2.0%石墨烯的银-石墨烯复合材料,并对复合材料进行销盘式摩擦磨损试验以研究其大气环境滑动摩擦磨损性能。研究结果表明,因石墨烯易团聚,石墨烯含量限于1.5%时能够有效改善复合材料的性能。与未增强的银相比,由于在接触表面形成自润滑碳质膜,银-石墨烯复合材料表现出较低的摩擦系数、较少的磨损量和较低的接触表面温度。随石墨烯含量的增加,复合材料的摩擦系数和磨损量均下降。复合材料的主要磨损机制为粘着磨损和磨料磨损。     

石墨对C/Cu复合材料微观组织及摩擦磨损性能的影响

利用机械合金化和放电等离子烧结技术制备C/Cu复合材料,用扫描电镜、透射电镜、X射线衍射仪、显微硬度计和销-盘摩擦磨损试验机对复合粉末和烧结体的组织结构、硬度、摩擦学行为进行了分析.结果表明:C/Cu复合粉末中Cu相粉末由纳米/亚微米复合颗粒组成,石墨主要以纳米层片状结构和非晶态存在,放电等离子体烧结体组织致密、细小且均匀,随着碳含量增加,烧结体的硬度与密度减小;C/Cu复合材料烧结样品在摩擦过程中形成润滑膜,表现出较低的摩擦系数和良好耐磨性,其磨损机制主要为氧化磨损、粘着磨损和剥层磨损.     

Influence of graphite content on sliding wear characteristics of CNTs-Ag-G electrical contact materials

CNTs-Ag-G electrical contact composite material was prepared by means of powder metallurgical method. The influence of the graphite content on sliding wear characteristics of electrical contact levels was examined. In experiments, CNTs content was retained as 1% (mass fraction), and graphite was added at content levels of 8%, 10%, 13%, 15% and 18%, respectively. The results indicate that with the increase of graphite content, the contact resistance of electrical contacts is enhanced to a certain level then remains constant. Friction coefficient decreases gradually with the increase of graphite content. Wear mass loss decreases to the minimum value then increases. With the small content of graphite, the adhesive wear is hindered, which leads to the decrease of wear mass loss, while excessive graphite brings much more worn debris, resulting in the increase of mass loss. It is concluded that wear mass loss reaches the minimum value when the graphite mass fraction is about 13%. Compared with conventional Ag-G contact material, the wear mass loss of CNTs-Ag-G composite is much less due to the obvious increase of hardness and electrical conductivity, decline of friction surface temperature and inhibition of adhesive wear between composites and slip rings.     

增强颗粒对镁基复合材料磨损性能的影响(英文)

研究增强颗粒Mg2Si对镁基复合材料摩擦磨损性能的影响,讨论Si加入量、载荷和滑动速度对Mg2Si/AM60镁基复合材料磨损性能的影响。结果表明,向镁合金中加入合金元素Si,可原位生成增强颗粒Mg2Si,增强颗粒Mg2Si可明显提高AM60镁合金的磨损性能。随着载荷和滑动速度的增加,AM60镁合金和Mg2Si/AM60镁基复合材料的磨损量都增大。AM60镁合金的磨损机制为粘着磨损。随着载荷的增大,Mg2Si/AM60镁基复合材料的磨损由磨粒磨损向粘着磨损转变。     

粉煤灰/铝-镁合金复合材料的微观组织及摩擦磨损性能

采用粉末冶金法制得粉煤灰/Al-25%Mg复合材料,研究不同粉煤灰含量对复合材料微观组织、硬度和摩擦磨损性能的影响,采用扫描电子显微镜观察复合材料的磨损表面形貌,并对其磨损机制进行探讨。结果表明:随着粉煤灰含量的增加,复合材料的硬度呈现先增大而后减小的趋势;在较低粉煤灰含量和较低载荷下,该复合材料的摩擦因数均低于基体铝合金的,并且随粉煤灰含量的增加复合材料的耐磨性有所提高,复合材料的磨损机制主要为粘着磨损和磨粒磨损;在较高粉煤灰含量和较高载荷下,该复合材料的磨损机制转化为以剥层磨损和磨粒磨损为主。     

Friction and wear properties of casting in-situ silicon particle reinforced ZA27 composites

The effects of silicon particle content and testing temperature on friction and wear properties of casting in-situ silicon particle reinforced ZA27 composites were investigated. The wear mechanisms were mainly discussed by observations of both worn surfaces and their side views. The results indicated that the variations of wear resistance with increasing of silicon particle content, at all of the testing temperatures applied, showed a similar tendency with a manner of non-monotonous change. It was surpdsed that the wear resistance decreased with the increase of silicon particle content from 2 vol.% to 5 vol.%, while it increased when the content was less than 2 vol.% or more than 5 vol.%. Similarly, the friction coefficient also did not change monotonously. The dominative wear mechanism changed from a relatively severe regime of plastic deformation accompanied by adhesion wear to a mild regime of smear, then to a very severe regime of severe plastic deformation induced wear, and finally again to a relatively mild regime of smear accompanied by abrasive wear as the silicon content increased. The wear resistance always decreased with elevating testing temperature, but the decrease ranges were different for the composites with different silicon contents. The friction coefficients changed irregularly for the different composites with the increase of testing temperature. Correspondingly, the wear mechanism alternated from a mild regime of smear accompanied by abrasive wear to a severe regime of plastic deformation accompanied by adhesion wear.     

三维网络陶瓷增强铝基复合材料的干摩擦磨损性能

设计和制备了一种新型的三维网络陶瓷(骨架)增强铝合金复合材料.研究了铝合金及不同成分复合材料在不同温度及载荷下的摩擦系数和磨损率;用扫描电镜(SEM)观察其磨损表面,并分析了三维网络陶瓷(骨架)对铝合金磨损机制的影响.结果表明:复合材料的耐磨性远优于铝合金,而且随着三维网络陶瓷体积分数、温度及载荷的增加,复合材料的抗磨损性能明显提高;这种新型复合材料的摩擦系数随载荷变化保持稳定;在很宽的温度范围内,摩擦系数的稳定性均优于铝合金.这是由于三维网络陶瓷在磨损表面形成硬的微凸体起承载作用,其独特的结构制约了基体合金的塑性变形和高温软化,有利于磨损表面氧化膜的留存.     

Evaluation of sliding wear behavior of graphite particle-containing magnesium alloy composites

1 Introduction More and more magnesium alloy products have been used in automobile and aerospace industries due to their low density, high specific strength and specific stiffness, good damping characteristic, excellent machineability and castability, etc…     

La_2O_3填充PA1010复合材料的摩擦磨损性能

采用热挤压方法制备了不同La2 O3含量的尼龙 10 10 (PA10 10 )复合材料。测定了复合材料的密度和硬度 ,在MM 2 0 0型环块试验机上考察了其摩擦磨损性能。用光学显微镜观察了材料表面磨痕和转移膜形貌。结果发现 :La2 O3能显著改善PA10 10的摩擦学性能 ,尤其是填充量为 15 %的PA10 10复合材料减摩耐磨性能最佳 ,其摩擦系数从未填充的 0 .87降到 0 .3 3 ,磨损率降低近 1个数量级。PA10 10的磨损主要表现为严重犁削、粘着、疲劳和塑性变形 ,其转移膜不均匀 ,且有脱落现象。PA10 10 15 %La2 O3复合材料的磨损主要表现为轻微犁削 ,其转移膜薄而致密 ,且均匀光滑。这与二者的耐磨性能相一致     

T6热处理对SiCp/Al复合材料摩擦磨损性能的影响

采用粉末冶金法制备出不同SiC颗粒体积分数(30%、35%和40%)的SiCp/Al复合材料。采用MMU-5GA微机控制真空高温摩擦磨损试验机对比研究SiCp/Al复合材料在不同体积分数以及T6热处理前后情况下平均摩擦因数和磨损率的变化,通过扫描电镜分析了SiCp/Al复合材料表面磨损形貌,探讨了摩擦磨损机理。试验结果表明,SiC颗粒体积分数在30%~40%变化时,随其体积分数增加耐磨性下降。SiC颗粒体积分数在30%~35%范围内,SiC颗粒与基体结合较好,SiC颗粒作为硬质点起到抵抗磨损和限制基体合金塑性变形产生磨损的双重作用;但SiC含量过多时,颗粒与基体的结合不紧密,磨损时颗粒极易脱落,复合材料耐磨性降低;T6热处理后复合材料的平均摩擦因数和磨损率均降低,这是由于热处理后试样强度及硬度提高,从而提高了试样的耐磨性;常温下复合材料在磨损初期的磨损机理主要以磨粒磨损为主,而在磨损期则为磨粒磨损与剥落磨损共存。     

Effect of graphite particle size on wear property of graphite and Al_2O_3 reinforced AZ91D-0.8%Ce composites

The graphite particles and Al_2O_3 short fibers reinforced AZ91D-0.8%Ce composites were fabricated by squeeze-infiltration technique.The researches about the effects of different graphite particle sizes on the microstructure and wear property of the composites were performed under the condition of constant contents of graphite particles and Al_2O_3 short fibers.The results reveal that the grain size of the composites changes less when the graphite particle size descends.Moreover,Ce enriches around the gr...