Effect of dual-scale FeCrSi phase on the strength and conductivity of Cu-2.5Fe-0.3Cr-0.2Si alloy

Abstract

A new dual-scale (submicron and nanoscale) FeCrSi ternary second-phase has been successfully constructed in designed Cu-2.5Fe-0.3Cr-0.2Si alloy. The synergistic addition of Cr and Si promotes the transformation of the submicron Fe phase morphology from “square” to “flower” shape in as-cast alloys. The orientation relationship between nanoscale FeCrSi phase and Cu matrix is: [011] Cu//[01‾1] Fe11CrSi4 and the misorientation angle between the (200) of the Cu matrix and the (022) of the Fe11CrSi4 phase is about 4°. After three-stage thermomechanical treatment, the tensile strength and electrical conductivity of the alloy are 435 MPa and 70.52 %IACS, respectively. According to the calculated results, precipitation strengthening and substructure strengthening play an important role in the strengthening of Cu–Fe–Cr–Si alloys. With the addition of Cr and Si, the precipitation of the second phase in the alloy is promoted, which also leads to the improvement of the electrical conductivity and mechanical properties of the alloy.