Dynamic Tensile Extrusion Behavior of Fine-Grained Copper Fabricated by Powder Injection Molding

Abstract

The dynamic tensile extrusion (DTE) behavior and microstructural evolution of fine-grained (FG, ~1 μm c, and the FG-150 Cu was fabricated by annealing the UFG-B Cu bar at 150 °C for 1 h. The DTE tests were performed with identical flyer velocities using an all-vacuum gas gun. The fragments and remnants were carefully recovered after the DTE tests and examined by electron backscattered diffraction measurement and a micro-Vickers hardness test. A strong dual + texture was developed during the DTE for both FGM and FGH Cu. In contrast to the outcome of the UFG-B and FG-150, little evidence of dynamic recrystallization taking place during the DTE in the FGM and FGH was found during analysis of the grain morphology and grain orientation spread. Premature failure based on void coalescence was induced at the vertex region of the FGM fragments due to pre-existing pores. The HIP treatment on the FGM Cu increased the relative density by reducing the pre-existing pores and, as a result, increased the DTE ductility of the FGH Cu.

Keywords

• fine-grained copper
• powder injection molding
• dynamic tensile extrusion
• microstructure
• fracture