Tie-Line Compositions of the γ and δ Phases in the Binary Re–Ni System

Abstract

Compositions with tie lines between the γ and δ phases in a binary Re–Cr–Ni system were investigated at 1423, 1573, and 1773 K by heat treating of Ar-arc-melted Re–40 at%Ni alloy. The microstructures of the Re–40 at%Ni alloy which had been water quenched after various heat treatment were observed and their concentration profiles for Re and Ni were measured using an electron probe microanalyzer. The Re–40 at%Ni alloy consisted of the γ and δ phases. The tie lined compositions of the γ and δ phases are summarized as follows (in at%); γ: 13.4 Re–86.6 Ni, δ: 71.7 Re–28.3 Ni at 1423 K, γ: 16.4 Re–83.6 Ni, δ: 69.3 Re–30.7 Ni at 1573 K, γ: 20.2 Re–79.8 Ni, δ: 65.3 Re–34.7 Ni at 1773 K. The Re–Ni alloy powder sintered using the Spark Plasma Sintering (SPS) method were investigated. Solubility limit of Ni in the δ phase in the binary alloy system at 1423 K was found to be 28.3 at%Ni.