Enhanced hot deformation property of Al2O3/Cu–Cr composite fabricated by internal oxidation

Abstract

The plastic deformability of ODS copper (Al2O3/Cu composite) always limits its widespread commercial application. In this work, the thermodynamically metastable mono-phase CuCr alloy was used to fabricate 2.5 vol%Al2O3/Cu-0.3 vol%Cr by an internal oxidation method with a subsequent solution treatment to improve the plastic deformation ability. The influence of dissolved Cr on the hot deformation property and dynamic recrystallization (DRX) behavior of Al2O3/Cu composite was studied, and the softening mechanism of Al2O3/Cu–Cr composite was revealed. The results show that the solid solution of Cr at high temperature can significantly improve the hot deformability of Al2O3/Cu composite. The maximum reduction of peak stress of 2.5 vol%Al2O3/Cu-0.3 vol%Cr composite is 57 % lower than that of 2.8 vol% Al2O3/Cu composite. Furthermore, the DRX critical values of 2.5 vol%Al2O3/Cu-0.3 vol%Cr composite is lower than that of 2.8 vol% Al2O3/Cu composite, and the DRX occurs earlier in Al2O3/Cu–Cr composite. The strain-compensated constructive model of Al2O3/Cu–Cr composite was established with a relation coefficient (R2) of 0.92, which proves the accuracy of the model. Finally, the hot processing map of Al2O3/Cu–Cr composite was constructed based on a dynamic analysis model, and the appropriate hot processing parameter of Al2O3/Cu–Cr composite was obtained with temperature of 1205 K–1223 K and strain rate of 0.022 s−1-0.97 s−1. The results are beneficial to improve hot deformation property of Al2O3/Cu–Cr composite and large sized bulks fabrication.