Sliding wear of cadmium against alumina

Abstract

As cast cadmium rods were slid against alumina at a load of 50 N and sliding speeds from 0.1 ms −1 to 4 ms −1. The wear characteristics of cadmium were related to its strain rate response under uniaxial compression between strain rates of 0.001 s −1 to 100 s −1 and temperatures in the range of 323 K to 573 K. In uniaxial compression, cadmium undergoes adiabatic shear banding at strain rates >10 s −1 and temperature up to 423 K. The intensity of this adiabatic shear banding reduces as the temperature is increased or the strain rate is reduced. This adiabatic shear banding is the only major microstructural response, in the present test region, that promotes cracking. At temperatures greater than 473 K the flow becomes homogeneous and no adiabatic shear banding is observed. The strain rates and temperatures existing during sliding are estimated using a simple non-iterative procedure and superimposed on the strain rate response map. At sliding speeds <1.0 ms −1 the near surface regions are likely to undergo adiabatic shear banding induced cracking. As the velocity of sliding increases the subsurface temperature increases making the regions close to the surface move towards regions of lower adiabatic shear banding intensity and finally to regions of homogeneous flow. It is seen that wear rates when the near surface strain rate response is expected to be adiabatic shear banding, which promotes cracking, is higher than when the near surface regions are in the homogeneous flow region. This indicates that when the strain rate response of a material promotes cracking at near surface regions the wear rates are higher. Thus, it can be said that the strain rate response of a material plays an important role in deciding the wear mechanism and wear rate of a material.