Phys.org September 6, 2022
While the impact of mechanical energy and heat on the friction and wear behavior of dry metallic interfaces has been the focus of extensive research in the past, the effect of extreme speeds on the near-surface deformation mechanisms in polycrystalline metals has remained poorly understood. An international team of researchers (Austria, UK) explored sliding velocities ranging from 10 to 2560 m/s via large-scale molecular dynamics simulations to identify three distinct deformation regimes in CuNi alloys. The microstructural response did not vary much for any of the considered systems up to sliding velocities of 40 m/s, but then evolved drastically up to a maximum value located between 320 and 1280 m/s depending on the composition. The degree of plastic deformation at the highest sliding speeds dropped down to a level almost as low as for the lowest sliding speeds which was attributed to a sharp increase in the contact temperature at these high sliding speeds, approaching or even exceeding the bulk melting temperature.This goes hand in hand with a decline in the contact area and the resistance to sliding. Their characterization of the non-linear and non-monotonic material response to increasing sliding velocities will aid the systematic selection of materials and the design of robust components for a variety of high-speed sliding and wear applications. According to the researchers characterization of the non-linear and non-monotonic material response to increasing sliding velocities will aid the systematic selection of materials and the design of robust components for a variety of high-speed sliding and wear applications…read more. TECHNICAL ARTICLE
Graphical abstract. Credit: Applied Materials Today, Volume 29, December 2022, 101588