Effect of elevated-temperature annealing on microstructure and properties of Cu-0.15Zr alloy
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Hunan Province Key Laboratory of Electronic Packaging and Advanced Functional Materials, Central South University, Changsha 410083, China;
3. College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha 410114, China)
2. Hunan Province Key Laboratory of Electronic Packaging and Advanced Functional Materials, Central South University, Changsha 410083, China;
3. College of Materials Science and Engineering, Changsha University of Science and Technology, Changsha 410114, China)
Abstract: Cu-0.15Zr (wt.%) alloy with uniform and fine microstructure was fabricated by rapid solidification followed by hot forging. Evolution of microstructure, mechanical properties and electrical conductivity of the alloy during elevated-temperature annealing were investigated. The alloy exhibits good thermal stability, and its strength decreases slightly even after annealing at 700 °C for 2 h. The nano-sized Cu5Zr precipitates show significant pinning effect on dislocation moving, which is the main reason for the high strength of the alloy. Additionally, the large-size Cu5Zr precipitates play a major role in retarding grain growth by pinning the grain boundaries during annealing. After annealing at 700 °C for 2 h, the electrical conductivity of samples reaches the peak value of 88% (IACS), which is attributed to the decrease of vacancy defects, dislocations, grain boundaries and Zr solutes.
Key words: Cu-Zr alloy; rapid solidification; annealing; microstructure; tensile strength; electrical conductivity