Creep behaviour of Al-0.2%Sc alloy processed by ECAP Method

An Al-0.2wt.%Sc aluminium alloy was subjected to equal-channel angular pressing (ECAP) at room temperature to refine its coarse – grain size corresponding to its as-received state. For this purpose the ECAP die was used which had a 90° angle between the die channels. By application of this method at room temperature an ultrafine-grained microstructure was achieved with the grain size of ~ 0.3mm after 8 ECAP passes by route BC. Following creep tests in tension were performed at 473 K and at applied stresses ranging from 10 to 50 MPa on ECAP material and, for comparison purposes, on unpressed one. The results indicate, that the creep resistance of ECAP material is markedly lower after 8 passes in comparison with creep behaviour of coarse – grained one. The detrimental effect of ECAP on the creep resistance is probably caused by increasing contribution of grain boundary sliding to the overall creep deformation