Extreme twinning and hardening of 316L from a scalable impact process

Abstract

A strain of 10% is applied to 316L stainless steel specimens at strain rates of 7.7 × 104 s−1, 200 s−1 and 50 s−1 using vaporizing foil actuator (VFA) technique for the highest strain rate and dynamic plastic deformation (DPD) for the lower strain rates. There is a dramatic increase in hardness with increasing strain rate, rising to over 2.2 GPa at the highest strain rate. While the average twin thickness remained similar across different strain rate regimes, a dense criss cross pattern of twins is formed at the highest strain rate from activation of deformation twinning in non-parallel planes. This shows promise for VFA driven flyers process as a method for surface modification and hardening.