基于离散元研究石墨对铜基石墨复合材料摩擦磨损性能的影响

文章利用离散元二维颗粒流程序(PFC2D)建立铜基石墨复合材料和45#钢摩擦副数值模型, 基于环-块滑动接触方式, 研究摩擦过程中摩擦界面动态变化规律及石墨粒径和体积分数对复合材料摩擦磨损性能的影响。结果表明: 复合材料和45#钢摩擦过程中, 在摩擦表面逐渐形成石墨润滑层, 使得摩擦副的接触由金属与金属接触逐渐转变为石墨与金属接触; 随着时步数增加, 材料摩擦系数整体下降并达到稳定; 石墨粒径增加, 摩擦系数增大, 磨损量先减少后增多, 石墨粒径为18μm时, 磨损量最少为 $ 1.65\times10^{-8}\ m^{3} $; 石墨体积分数增多, 材料摩擦系数降低, 磨损量先减少后增多, 石墨体积分数为12%时, 磨损量最少为 $ 1.61\times10^{-8}\ m^{3} $。

The numerical model of copper matrix graphite composite and 45# steel friction pair was established by two-dimensional particle flow code (PFC2D). Based on the ring-block sliding contact mode, the dynamic change law of friction interface during friction process and the influence of graphite particle size and volume fraction on the friction and wear properties of the composite material were studied. The results showed that the graphite lubrication layer was gradually formed on the friction surface of the composite material and 45# steel during the friction process, and the contact between the friction pair was gradually transformed from metal and metal contact to graphite and metal contact. With the increase of time steps, the friction coefficient of the material decreased as a whole and reached a stable fluctuation. With the increase of graphite particle size, the friction coefficient increased, and the wear amount first decreased and then increased. When the graphite particle size was 18 $ \mu $m, the minimum wear amount was $ 1.65 \times 10^{-8} $ m $ ^{3} $. With the increase of the graphite volume fraction, the friction coefficient of the material decreased, and the wear amount first decreased and then increased. When the graphite volume fraction was 12%, the minimum wear amount was $ 1.61 \times 10^{-8} $ m $ ^{3} $.