Microstructure and dynamic compression behavior of Cu-Cr-W alloy under different impact rates

Abstract

This study reports on the preparation of Cu-Cr-W alloys with varying Cr contents achieved through mechanical alloying and spark plasma sintering methods. Field emission scanning electron microscopy and transmission electron microscopy were employed to carefully observe and analyze the micro-morphological features, elemental composition, and microstructural details of the Cu-Cr-W composite powders as well as the alloy samples. The dynamic compression behaviors of Cu-Cr-W alloys under different impact rates were investigated using a Hopkinson pressure bar device. Electron backscatter diffraction was utilized to comprehensively assess the phase makeup, characteristics of grain boundaries, geometrically essential dislocation density, and inverse pole figures of the Cu-Cr-W alloy specimens after dynamic compression. Experimental results demonstrate that during the sintering process, Cr can react with the W phase to form a Cr_0.5W_0.5 solid solution. Additionally, the addition of Cr improves the uniformity of the dispersion of W particles in the Cu matrix. As the Cr content rises, the ability of the Cu-Cr-W alloy to resist dynamic compression improves significantly. This is mainly attributed to the synergistic effect of multiple strengthening mechanisms generated by Cr within the Cu-W alloy. For the Cu-W alloy doped with 4 at.% Cr, at impact rates of 2800–3000 s⁻¹ and 3800-4000 s⁻¹, its dynamic compressive yield strengths reach 839 MPa and 828 MPa respectively. Compared to the Cu-W alloy without the addition of the Cr element, these values are 32.1 % and 33.8 % greater.