A Study of the Strain Rate Microstructural Response and Wear of Metals

Titanium (Ti) and copper (Cu) pins were slid against alumina in a pin-on-disk machine at a load of 50 N and sliding speeds varying from $0.1 \hspace {2mm} to \hspace {2mm} 4 ms^{-1}$. The evolution of the microstructure in the subsurface of the material and the wear rate was co-related to the strain rate microstructural response of the material in uniaxial compression, at different strain rates $(0.1-100 \hspace {2mm} s^{-1})$ and temperatures (298-673 K). The strain rates and temperatures in the plastically deforming zone near the surface of the pins were determined using noniterative methods. The strain rates were found to be in the region of $100 \hspace {2mm} s^{-1}$ near the surface and decreases as one moves into the sub-surface of the pin. The temperatures increased as the speed increased. These estimated strain rates and temperatures were superimposed on the strain rate microstructural response maps of these materials. The uniaxial compression test results of Ti showed adiabatic shear banding as a microstructural mechanism that evolves at high strain rates $(\geq 10 \hspace {2mm} s^{-1})$ and lower temperatures (