Different Effects of Body-Centered Cubic and Face-Centered Cubic Chromium Precipitations on Mechanical Properties and Wear Resistance of Cu-Cr-Zr Alloy

• Published in: Journal of materials engineering and performance 2022-12, Vol.31 (12), p.9910-9920
• Main Authors: Liu, Dezhi, Huang, Baoxu, Wang, Changzheng, Ma, Jie, Zhao, Xingchuan
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Materials Science; Quality Control; Reliability; Safety and Risk; Technical Article; Tribology
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-022-07016-8

Commercial high strength and high electrical conductivity Cu-0.67Cr-0.3Zr alloy was directionally solidified and subsequent aged. The specific strengthening mechanism of FCC and BCC structured chromium precipitations was discussed in detail. The strengthen effect of FCC Cr precipitation with a size less than 35 nm follows shear strengthening mechanism, while that of BCC Cr precipitation with size greater than 1.4 nm follows non-shear strengthening mechanism. After aging treatment, the yield strength of the alloy with a solidification rate of 50 μm/s increases from about 140 to 205 MPa, which is due to the transformation of Cr precipitation from FCC to BCC. Besides, the matrix purification caused by phase transformation increases the electrical conductivity. In addition, the wear resistance of the alloy is also improved with the increase in strength. These excellent properties make the alloy have the potential to be competent as the high-speed railway contact lines.