Tribological Properties of Fiber and Particle Reinforced Hybrid Aluminum Composite

(1)通过针盘试验研究了添加Al_2O_3纤维和添加两种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4 μ m，体积分数为2% ~ 26%。Al_2O_3颗粒大小为0.6 ~ 20 μ m。将MMC（圆盘试样）与氮化SUS440B不锈钢（销试样）在载荷为10N、滑动速度为0.1m/s的条件下进行摩擦。用纤维和Al_2O_3颗粒增强铝可以提高干滑动磨损性能。在严重磨损初期，增强材料抑制了磨损裂纹扩展和塑性流动。增加纤维的体积分数提高了稳态轻度耐磨性，显然是通过形成均匀分散的粉碎纤维的硬表面，以及通过氧化接触面来防止粘附。增大颗粒尺寸可提高耐磨性。根据磨损率和SEM观察，将MMC的磨损机理分为三种类型，即；1.黏着磨损主要由基体材料和低体积分数的MMCf主导；高体积分数MMCf和小颗粒混合MMCf的三体磨粒磨损；大粒径混合MMC的两体磨粒磨损。(2)在空气和真空环境下，用0.45%碳钢对SiC颗粒增强Al复合材料进行摩擦试验。在空气中，SiC颗粒防止或减少严重磨损，但在初始阶段会磨损表面。增强后的稳态轻度磨损率略有提高，但随着颗粒体积分数的增加而增大。在真空条件下（5 × 10^<-4>Pa）， MMC的磨损率比在空气条件下的磨损率小约100倍，明显小于基体材料。特别是颗粒为20 μ m的MMC，由于磨损颗粒在摩擦表面之间转移而没有磨损。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