Effect of hot rolling on the enhancement of mechanical properties of low density Cu–Cr–Nb sintered alloy

Studies have been carried out on the effect of hot rolling on the enhancement of mechanical properties of sintered low density Cu–8 at.% Cr–4 at.% Nb alloy made from gas-atomised powders by vacuum hot pressing using varying pressure and temperature. The pressure is varied from 10 to 30 MPa whereas, 800, 900 and 1000 °C are three hot-pressed temperatures. Though hot rolling of porous low density hot-pressed samples results in near theoretical density, the hot-pressed sintered material with higher initial porosity shows lower strength and ductility after rolling. Hot-pressed compacts below certain density could not be rolled and the sample has cracked during rolling. The higher density material could be easily rolled and significant improvement in mechanical properties has been noticed. This has been attributed to the conversion of porosities into microscopic cracks which could not be healed due to the presence of Cr2Nb precipitates. Finally, structure property correlation has been established.

► Effect of hot rolling on mechanical properties of Cu–8Cr–4Nb (at.%) alloy is studied. ► Hot rolling of porous low density hot-pressed samples results in near theoretical density. ► Specimens with higher initial porosity show lower mechanical properties after rolling. ► Porosities could not be removed even after severe plastic deformation at high temperature.