Microstructure evolution and properties of multi-scale precipitate strengthened Cu-Cr-Nb alloy.

Cu-Cr-Nb alloys has become a key material for ITER plasma facing components (PFC) due to its excellent thermal stability. In this study, Cu-3.3Cr-1.6Nb (wt%) alloy was prepared through in-situ casting using Cu Cr and Cr Nb master alloy. The agglomeration and coarsening of Cr 2 Nb particles in Cu-Cr-Nb alloy are improved. The effect of aging temperature on the microstructure and properties of rolled Cu-3.3Cr-1.6Nb alloy. The results show that the aged Cu-3.3Cr-1.6Nb alloy contains multi-scale precipitation phases distribution with micron-level Cr 2 Nb (0.2–2 μm), Cr-rich phase (2.2 μm), nano-level Cr 2 Nb (13.1 nm) and nano-level Cr (9.3 nm). After aging at 450 °C for 0.5 h, the tensile strength and electrical conductivity of the aged alloy were 469 MPa and 78.5% IACS, respectively. According to TEM and EBSD analysis, the Cr 2 Nb particles did not grow during the aging and were pinned the grain boundaries to inhibit the growth of Cu matrix grains, which result in a good thermal stability of Cu-3.3Cr-1.6Nb alloy. This study provides a new method for preparing Cu-Cr-Nb alloy with high-strength, high-conductivity and high heat resistance by casting method. • the microstructure of aged Cu-3.3Cr-1.6Nb alloy contains micro-scale Cr 2 Nb and Cr, nano-scale Cr 2 Nb and Cr precipitates. • The agglomeration and coarsening of Cr 2 Nb particles in Cu-3.3Cr-1.6Nb alloy are improved. • Cu-3.3Cr-1.6Nb alloy has a good thermal stability. [ABSTRACT FROM AUTHOR]