High strength high electrical conductivity ultrafine-grained Al–Y alloy processed via cold drawing

Abstract

Strength and electrical conductivity are always mutually exclusive in Al conductor materials because most of the common strengthening method will inevitably increase their electrical resistance. In this work, an ultrafine-grained Al-7.5Y alloy with large amounts of stacking faults interior the Al grains was fabricated by multi-passes clod drawing. The results show that the cold drawing processed Al-7.5Y alloy shows a simultaneous increase in mechanical strength and conductivity compared to that of the as-cast alloy. After cold drawing, the ultimate tensile strength increases from 126 MPa to 232MPa; meanwhile, the conductivity increases from 49.94%IACS to 52.24%IACS. The potential strengthening mechanisms and conducting mechanism were explored based on the theoretical prediction and the experimental findings. The grain boundary strengthening and dislocation strengthening contribute a crucial part in the total strength. The increase of conductivity in Al–Y alloy is mainly attributed to the directionally aligned Al3Y particles along the drawing direction; meanwhile, the SFs play an essential role in maintaining high strength and high conductivity.