The mechanical property and electrical conductivity evolution of Al–Fe alloy between room temperature and elevated temperature ECAP

Abstract

Ultra-fine grained Al–Fe alloy rods were manufactured by Equal-channel Angular Pressing (ECAP) at the two temperatures (room temperature (RT) and elevated temperature (ET)). Microstructure, mechanical properties, and electrical conductivity exhibited an abnormal evolution between RT-ECAP and ET-ECAP. A strong dissolution of micron Al3Fe and Al6Fe precipitations has been demonstrated in this immiscible Al–Fe alloy systems at such a few strains during the ET-ECAP. The Fe solid atoms dissolved back into the matrix, induced high-density dislocation and accelerated the grains refinement. It contributed to the finer grains, higher strength as well as dramatic decreased electrical conductivity in ET-ECAP. Meanwhile, the agglomeration and growth of nanoparticles decreased its dispersity in matrix distribution in RT-ECAP, leading to strength in RT-ECAP shown a stable or even decrease tendency, while strength constantly grew in ET-ECAP. Based on the feature of dissolution and precipitation, a high strength combined with a considerable electrical conductivity of this investigated Al–Fe alloy has been simultaneously achieved by the modified ECAP routes using 4 ECAP passes at room temperature and then another 4 passes at elevated temperature. The yield stress (~178.0 MPa) and electrical conductivity (~61.55%) are superior to the convention ECAP routes of 8 RT-ECAP passes and 8 ET-ECAP passes.