Tribological Properties of Fiber and Particle Reinforced Hybrid Aluminum Composite

(1)在销盘试验机上研究了添加Al_2O_3纤维和部分添加Al_2O_3颗粒的ADC-12压铸铝的摩擦学性能。Al_2O_3纤维直径为4µm，纤维体积分数为2%~26%，长度为200~40µm，Al_2O_3颗粒大小为0.6~20µm，摩擦载荷为10N，滑动速度为0.1m/次，Al_2O_3纤维和Al_2O_3颗粒增强的Al_2O_3干滑动磨损性能较好。在严重磨损初期，增强体阻止了磨损裂纹扩展和塑性流动。纤维体积分数的增加改善了稳态温和的耐磨性，这明显是通过形成均匀分散的纤维的硬表面，并通过接触表面的氧化来防止粘连。增加颗粒的尺寸提高了耐磨性。来自t…结合磨损率和扫描电子显微镜观察，MMC的磨损机制可分为三种类型：1.以基体材料为主的粘着磨损和低体积分数的MMC；2.高体积分数的MMC和小颗粒混杂MMC的三体磨料磨损；3.大颗粒混杂MMC的两体磨粒磨损。(2)0.45%碳钢在空气和真空环境中用销盘式摩擦磨损试验研究了碳化硅颗粒增强铝基复合材料。在空气中，碳化硅颗粒防止或减少了严重的磨损，但在初始阶段会磨损对接表面。随着颗粒体积分数的增加，稳态温和磨损率略有提高，但随颗粒体积分数的增加而增大。在真空中(5×10；-4&gt；Pa.)，MMC的磨损率比空气中的磨损率小约100倍，远小于基体材料的磨损率。尤其是颗粒尺寸为20微米的MMC，由于磨粒在摩擦表面之间的转移，未发生磨损。较少

(1) Tribological properties of ADC 12 die casting aluminum with fibers of Al_2O_3, and some with and Al_2O_3 particles added were investigated in a pin-on-disk test. The Al_2O_3 fibers were 4 mu m in diameter : they were added in volume fractions from 2% to 26%.and their length ranged from 200 to 40 mu m. The particles of Al_2O_3 of ranged in sizes from 0.6 to 20 mu m. The MMC (disk test piece) were rubbed against nitrided SUS440B stainless steel (pin test piece) with a load of 10N and a sliding speed of 0.1m/s.Aluninum reinforced with fibers and particles of Al_2O_3 can improve dry sliding wear resistance. Reinforcements prevented wear crack propagation and plastic flow in the initial severe wear. Increasing volume fraction of fibers improves steady state mild wear resistance, apparently by the formation of a hard surface of uniformly dispersed crushed fibers, and by oxidation of the contact surfaces to prevent adhesion.Increasing size of particles improves the wear resistance. From t … More he wear rate and SEM observations, the wear mechanism modes of MMC are divided into three types, namely ; 1.Adhesive wear dominated by matrix material, and MMCf with low volume fraction, 2.Three body abrasive wear for MMCf with high volume fraction, and hybrid MMC with small particles, 3.Two body abrasive wear for hybrid MMC with large particle diameter.(2) SiC particle reinforced Al composites were rubbed by 0.45% carbon steel using pin-on-disk apparatus in air and vacuum environments. In air, SiC particles prevent or decrease severe wear but abrade the counterface in the initial stage. The steady state mild wear rate slightly improved by reinforcements but became larger with an increase of volume fraction of particle. In vacuum (5 x 10^<-4>Pa), the wear rate of MMC,which was about 100 times smaller than that in air, was considerably smaller than that of matrix material. Particularly, the MMC with particle of 20 mu m did not wear because the wear particles transfered between rubbing surfaces. Less