Characterization of Microstructure and Mechanical Properties of CuCr Alloy Produced by Stir Casting


The relatively low mechanical properties of pure copperat low and high temperature made it very limitedapplications. The mechanical properties of the copper canbe improved by adding a small amount of elements such asCr. This work consists of four CuCr alloy castings (0.3, 0.8,1.2 and 1.5%) by using the stir casting method in an argonatmosphere. Then, the heat treatment was done for thesealloys which included solution treatment and aging. Heattreatment was treated at 980 ° C for 1 hour, then waterquenching, followed by an aging treatment at 480 ° C for2.4 and 6 hours. The Optical Microscopy and the ScanningElectron Microscopy (SEM) with (EDS) were used to studythe microscopic structure of the produced alloys. The resultsshowed that the mechanical properties of copper increasedwith increasing chromium content. The microstructure ofthe castings consist of the dendiritic structure, columinarand segregation. It has been also indicated that after heattreatment and aging, the microstructure changed to finegrains and the clusters disappeared. XRD showed a α-Cuphase and a small amount of CrO2 in microstructures. Thehighest value of hardness and the ultimate tensile were 101Hv and 239.12 MPa, respectively. They were achieved at1.5wt% addition of Cr at 480oC and 4hrs aging.