The Cu-Ag-Cr alloy is a kind of aging hardening copper alloy and has excellent combination properties of high strength and good electrical and thermal conductivity. In the present investigation, the aging precipitation behavior of Cu-Ag-Cr alloy is studied, and the effects of aging processes on the microstructure and properties are discussed. Emphasis is on the correlation between the coherency and coarsening behavior of the Cr precipitates. When the alloy aging at low annealing temperatures, the homogeneous dispersed Cr precipitates are observed to be approximately spherical and keep coherent with Cu matrix in the Cu-Ag-Cr alloy, the coherency is lost between at 450°C~520°C, coherency on coarsening process of Cr precipitates at high annealing temperatures, the radium for coherent / semi-coherent transition of the Cr precipitates is determined from TEM micrographs as 15-45nm. Aging in the intermediate stage, coherent and semi-coherent particles can co-exist(15<r<45nm). The precipitation can be accelerated by cold deformation before aging, the 60% deformed Cu-Ag-Cr alloy aging at 480°C for 1h, the hardness and electrical conductivity can respectively reach to 158HV and 85%IACS.
Aging precipitation behavior and mechanical properties of Inconel 617 superalloy
