Measurements of the Strain-Rate Dependence of Spallation Strength in 304L Stainless Steel

The spallation strength of a metal is known to be highly dependent on the material properties and the loading history. One of the most influential loading variables on the spallation strength is the tensile strain-rate. We present a series of experiments that probe the influence of tensile strain-rate and duration under tension on the spallation strength of 304L stainless steel. Two experimental configurations were utilized in this work. The first contained five individual impactor-sample pairs of differing thickness contained on a single projectile/target. This provided spallation strength measurements at five unique tensile strain-rates but identical peak compressive stress. The second experimental configuration used a wedge-shaped impactor to generate a continuously varying spall plane location along the sample, changing the duration under tension while the strain-rate and peak compressive stress remained constant. In each experiment, the 304L stainless steel samples were recovered and post-mortem computed tomography (CT) and scanning electron microscopy (SEM) was conducted to provide insight on the mechanisms of void nucleation and growth.