High temperature tribological behaviors of aluminum matrix composites reinforced with solid lubricant particles

固体润滑颗粒增强铝基复合材料的高温摩擦学行为

The AA6061-10 wt.%B4 C mono composite, AA6061-10 wt.%B4 C-Gr(Gr: graphite) hybrid composites containing 2.5, 5, and 7.5 wt.% Gr particles, and AA6061-10 wt.%B4 C-Mo S2 hybrid composites containing 2.5, 5, and 7.5 wt.% Mo S2 particles were fabricated through stir casting. The dry sliding tribological behaviors of the mono composite and hybrid composites were studied as a function of temperature on high temperature pin-on-disc tribotester against EN 31 counterface. The wear rate and friction coefficient of the Gr-reinforced and Mo S2-reinforced hybrid composites decreased in the temperature range of 30-100 ℃ due to the combined lubrication offered by the wear protective layer and its solid lubricant phase. Scanning electron microscopy(SEM) observation of the worn pin surface revealed severe adhesion, delamination, and abrasion wear mechanisms at temperatures of 150, 200, and 250 ℃, respectively. At 150 ℃, transmission electron microscopy(TEM) observation of the hybrid composites revealed the formation of deformation bands due to severe plastic deformation and fine crystalline structure due to dynamic recrystallization.

通过搅拌铸造法制备AA6061-10wt.%B4C单一复合材料,Gr(Gr为石墨)颗粒含量为2.5、5、7.5 wt.%的AA6061-10wt.%B4C-Gr混杂复合材料,和Mo S2颗粒含量为2.5、5、7.5wt.%的AA6061-10wt.%B4C-Mo S2混杂复合材料。采用销-盘式摩擦试验机(对磨材料为EN31)研究温度对复合材料干滑动摩擦行为的影响。在30~100℃的温度范围内,由于摩擦保护层及其固体润滑相的共同润滑作用,Gr增强和Mo S2增强的混杂复合材料的磨损率和摩擦因数均下降。对磨损表面进行扫描电镜观察,结果表明,150、200和250℃下的磨损机制分别为重度粘着磨损、剥层磨损和磨粒磨损。透射电镜结果显示,150℃时,混杂复合材料中形成了变形带和精细的晶体结构,分别是由严重的塑性变形和动态再结晶造成的。