The effect of high pressure torsion (HPT) at room temperature and subsequent HPT at elevated temperatures on the microstructure, mechanical and electrical properties of the Al-0.4Zr alloy has been investigated. It has been shown that the HPT treatment of the alloy with an ultrafine grained structure at elevated temperatures led to a drastic increase in strength, which is accompanied by an increase in conductivity. Experimental values and theoretical estimations of the yield stress and electrical resistivity at 77 K; are compared. Possible reasons for the observed strengthening effect are discussed.