Influence of hot isostatic pressing and forging on the microstructure and mechanical properties of Cu-3Ag-1Zr alloys

Abstract

Cu-3 wt% Ag-1 wt% Zr alloys were well prepared by gas atomization followed by hot isostatic pressing (HIP) and forging. The effects of HIP temperature on the microstructure and mechanical properties of the as-HIPed and as-forged alloys were investigated, respectively. The alloy HIPed at 830 °C has an inhomogeneous microstructure with prior particle boundaries and fine network structure, and forging crushes the network structure into Cu4AgZr particles of 100–200 nm. The alloy HIPed at 950 °C exhibits a homogeneous microstructure with uniformly distributed Cu4AgZr particles in the range of 5 μm, but forging has less effect on the particles. A relatively lower HIP temperature leads to the formation of finer grains and better grain-further-refining in the subsequent forging. Consequently, before and after forging, the alloy HIPed at 830 °C has a higher hardness and strength compared with that HIPed at 950 °C. However, conventional solid solution and age-treatment have a limited effect on the mechanical properties of the alloys. The alloy HIPed at 830 °C followed by forging and aging has a yield strength, ultimate tensile strength, and elongation of 321 MPa, 454 MPa, and 39%, respectively. Keywords: Cu-Ag-Zr alloy, Gas atomization, Hot isostatic pressing, Forging, Microstructure, Mechanical properties