球形压头的滑动速度对材料微米划痕响应的影响

在恒定的法向载荷下,使用Rockwell C 120°金刚石压头对聚碳酸酯(PC)、熔融石英、紫铜和镁合金AZ31进行微米划痕测试,研究滑动速度对试样划痕响应的影响.压入深度小于压头的球锥转变深度,确保仅有压头顶端的圆球部分与试样接触.结果表明:随着滑动速度的增加,压入深度、残余深度和划痕沟槽的宽度均非线性减小,划痕硬度和弹性恢复率均非线性增大;PC和紫铜的划痕摩擦系数先增大后减小,PC的黏弹性行为对其摩擦响应有显著影响;熔融石英的划痕摩擦系数先增大后减小,最后趋于稳定;镁合金AZ31的划痕摩擦系数先减小后增大.熔融石英、紫铜和镁合金AZ31的划痕摩擦系数的变化趋势可通过几何接触模型进行解释.

Effect of sliding velocity of a spherical indenter on microscratch response of materials

Microscratch test was carried out on polycarbonate (PC), fused silica, copper and magnesium alloy AZ31 with a Rockwell C 120° diamond indenter to study the effect of sliding velocity on the scratch response of the samples under constant normal loads. The penetration depth is smaller than the transition depth from the sphere to cone of the indenter, so that only the sphere at the top of the indenter makes contact with the samples. The results show that the penetration depth, the residual depth and the width of the scratch groove decrease nonlinearly with the increase of sliding velocity. The scratch hardness and elastic recovery rate increase nonlinearly as sliding velocity increases. The scratch friction coefficient of PC and copper firstly increases and then decreases with the increase of sliding velocity. The viscoelastic behavior has a significant effect on the friction response of PC. The scratch friction coefficient of fused silica firstly increases, then decreases and finally remains almost stable with the sliding velocity. The scratch friction coefficient of magnesium alloy AZ31 initially decreases and then increases as sliding velocity increases. The changing trend of the scratch friction coefficient of fused silica, copper and magnesium alloy AZ31 can be explained by the geometrical contact model.