MoSi2增强镍基合金复合材料的摩擦磨损性能研究

采用真空热压法制备MoSi2增强镍基合金复合材料,并考察了其在室温下同Si3N4陶瓷球配副时的摩擦磨损性能.结果表明:加入MoSi2增强相可以显著提高镍基合金复合材料的显微硬度及其摩擦磨损性能;当添加MoSi2质量分数为30%时,复合材料的显微硬度最高、磨损率最低;当MoSi2质量分数分别为20%时,复合材料的摩擦系数最小;随着MoSi2含量增加,复合材料的磨损机理逐渐由塑性变形向脆性微断裂转变,其原因在于MoSi2硬质颗粒对镍基合金基体具有明显的弥散强化效应,并能够在摩擦磨损过程中起到有效的承载作用.为了保证镍基合金复合材料的摩擦磨损性能处于最佳状态,MoSi2增强相的最佳含量应控制在30%.

Friction and Wear Behavior of Ni-based Alloy Reinforced with MoSi2

Ni-based alloys reinforced with MoSi2 were fabricated by hot pressing and sintering in vacuum. Tribological properties of the composites were evaluated by a THT friction and wear tester. Results indicate that addition of MoSi2 contributed greatly to the increase of microhardness and wear resistance of the Ni-based alloy and it had minor effect on the friction coefficient. The composite containing 30wt% MoSi2 had the highest microhardness and it exhibited better wear resistance. While the composite with 20wt% MoSi2 exhibited the lowest friction coefficient, thus it is suggested to keep the content of MoSi2 in the reinforced Ni-based alloy composite to be 30%, so as to acquire the optimized mechanical and tribological properties. The wear mechanism of composites varied from severe plastic deformation to microcracking with addition of MoSi2. In general, wear resistance of the composites reinforced by MoSi2 was attributed to the effect of dispersion strengthening and load-carrying of the MoSi2 hard particulates.