Microstructure and properties of powder metallurgy Cu-1%Cr-0.65%Zr alloy prepared by hot pressing

Powder metallurgy Cu-1Cr-0.65Zr (wt%) alloy was fabricated using Cu, Cr, and ZrH2 powders as initial materials by hot pressing at 950 degrees C for 4 h under 27.7 MPa. Microstructure was observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). Mechanical and electrical properties were also analyzed. It was found that an appropriate heating treatment could result in the formation of fine and homogeneously dispersed coherent nano-precipitates, relative to Cr phase with BCC structure and Cu5Zr. The aging treatment induced the first increase and then decrease of hardness with the prolongation of aging time. The highest hardness of 141 HV was achieved when aging at 450 degrees C for 4 h, following the strength of 397 MPa with an elongation of 23%. However, the electrical conductivity was only 78.3% IACS (International Annealing Copper Standard). It was determined that the effect of Cr particles on strength was more important than that of Cu5Zr. (C) 2016 Elsevier Ltd. All rights reserved.