Effect of Fe on the constitution of Cu–W alloys at 1200 °C

Abstract The phase equilibria of the Cu–W–Fe system were studied experimentally, except for the Cu–Fe limit region. The isothermal section at 1200 °C was determined from analysis of the phases formed after thermal treatment. Forced sedimentation and immersion techniques were used for a reliable sampling of the liquid involved in the liquid/solid phase equilibria. Equilibrium results were complemented by diffusion couple-type experiments. From the Cu–W side, the phase fields formed with increasing Fe content were: {Cu-based liquid+b.c.c. W}, {Cu-based liquid+b.c.c. W+Fe 7 W 6 }, {Cu-based liquid+Fe 7 W 6 }, {Cu-based liquid+Fe 7 W 6 +b.c.c. Fe} and {Cu-based liquid+b.c.c. Fe}. In the ternary system the homogeneity ranges of the Cu-based liquid, b.c.c. W and Fe 7 W 6 are very similar to those of the binary phases.