Determination of the Mechanical Properties of Metals at Very High Strain Rates

Metals are widely used in the defense industry and civil engineering and an understanding of the mechanical properties of metals under intense dynamic loadings is of great significance for the design and assessment of weapons and protective structures. In this paper, the dynamic yield strengths (HELs) of 93 tungsten alloy and 921A steel at very high strain rates are determined by plate impact tests using a two-stage light gas gun system. The paper consists of three parts: firstly, the basic principle of the plate impact experiment is briefly introduced; secondly, the experimental data is analyzed in some details; finally, the dynamic yield strengths of 93 tungsten alloy and 921A steel at very high strain rates are determined. The experimental results show that the dynamic yield strengths of 93 tungsten alloy at strain rates of 1.7 × 10⁵ s⁻¹ and 3.1 × 10⁵ s⁻¹ are 2.10 GPa and 2.78 GPa respectively and the dynamic yield strengths of 921A steel at strain rates of 3.6 × 10⁵ s⁻¹, 4.7 × 10⁵ s⁻¹ and 6.2 × 10⁵ s⁻¹ are 2.08 GPa, 2.67 GPa and 3.15 GPa, respectively. The experimental results also show that the dynamic increase factors for 93 tungsten alloy and 921A steel at very high strain rates are between 2 and 3.