Comparison of Dislocation Structures in Cu Deformed at Strain Rates from Quasi-Static to Shock Loading Using X-ray Line Profile Analysis

Abstract

Polycrystalline copper samples were deformed in the range of strain rate between ~10−3 and 107 s−1 using a material testing machine, split Hopkinson pressure bar and electric gun. The quasi-static and Hopkinson bar samples were compressed at the strains of 0.1 and 0.4, and the electric gun samples were compressed at the shock pressures of 19, 25, 35 and 49 GPa. The dislocation structure in the recovered samples was determined using high-resolution X-ray line profile analysis. Compared to the quasi-static and Hopkinson bar tests, different characteristics of the evolution of dislocation density and arrangement were found in the planar plate impacts of the electric gun. The correlation between the flow stresses and the dislocation densities in the samples was discussed using the Taylor equation.

Keywords

• OFHC copper
• compression
• electric gun
• strain rate
• dislocation structure
• deformation mechanism