不同温度下Cu/FeS复合材料摩擦过程中组织演变的分子动力学模拟研究

Molecular Dynamics Simulation of the Microstructure Evolution of Cu/FeS Composite in Friction under Different Tempertures

通过计算机模拟的方法对不同温度下Cu//Cu/FeS摩擦副的摩擦性能进行计算研究,结果发现:当环境的温度在500 K时,摩擦副的摩擦系数出现第一个谷值,而此时金属铜发生再结晶,黏着磨损更为明显;700 K时,黏着层数减小而摩擦系数却有所增大,主要是由于复合材料内部的FeS结构发生转变造成.计算结果还证明:在高温情况下,增强相FeS存在先分解再重新结合的2个过程,并指出Cu/FeS复合材料在900 K时,仍然具有很好的减摩耐磨作用.还对不同温度摩擦时复合材料内部的组织演变过程进行系统分析,分析结果表明,随着温度的升高,FeS的结构发生演变,从六方NiAs型超结构相转变为简单NiAs型结构相,并且随着温度的升高,FeS结构的c/a也在不断减小,这些都影响着复合材料的摩擦性能.

Tribological property of Cu//Cu/FeS tribopair under different temperatures was simulated by molecular dynamics. The tribopair exhibited a low value of friction coefficient at 500K, when there was a severe adhesion wear due to recrystallization of Cu. At 700 K, the number of adhesion layers decreased and friction coefficient increased a little, this is because that FeS structured changed. The simulation proved that FeS experienced two processes of decompose and reunite, and Cu/FeS composite exhibited good tribological performance at 900 K. The evolution of structure was analyzed systematically. With increase of temperature, FeS structure changed from hexagonal NiAs- type superstructure to simple NiAs -type phase, and the c/a ratio decreased gradually, which affects the performance of the composite.