Exploring the strength and ductility improvement of Cu–Al alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2020-06, Vol.786, p.139441, Article 139441
• Main Authors: Ren, C.X., Wang, Q., Hou, J.P., Zhang, Z.J., Yang, H.J., Zhang, Z.F.
• Format: Article
• Language: English
• Subjects: Aluminum base alloys; Construction; Copper; Copper base alloys; Cu-Al alloy; Ductility; Elongation; Gradient structure; Grain size; Solid solutions; Solution strengthening; Spinning (materials); Strength; Work hardening
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2020.139441

Synchronous improvement of the strength and ductility for metallic materials is an everlasting object as the good service performance. In this study, the yield strength (σYS) and uniform elongation (εUE) of Cu-Al alloys with three Al contents, nine grain sizes induced by the controlled annealing treatment, and three gradient structures induced by surface spinning strengthening (3S) treatment were explored. Results show that the σYS and εUE may be enhanced synchronously by increasing Al content from 5Al, 8Al to 11Al, while the σYS decreases and εUE increases when increasing grain size from ultra-fined grain, fine grain to coarse grain, and the σYS increases obviously and εUE decreases slightly by constructing the gradient layer. The trade-off relation between strength and ductility is broken through by increasing Al content, however cannot be broken through by controlling grain size, and cannot be directly broken through by constructing gradient structure. In addition, the Cu-Al alloys with the high Al content, fine grain and gradient layers obtain the superior combination of strength and ductility, and the reason is that the solid-solution strengthening, boundary strengthening and work hardening are combined together. Inspired by these, the composition design, grain size regulation, and gradient structure construction may be considered as the three feasible approaches to enhance the strength and ductility of metallic materials.