A study of precipitation strengthening and recrystallization behavior in dilute Al–Er–Hf–Zr alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2015-07, Vol.639, p.307-313
• Main Authors: Wu, H., Wen, S.P., Wu, X.L., Gao, K.Y., Huang, H., Wang, W., Nie, Z.R.
• Format: Article
• Language: English
• Subjects: Aging (metallurgy); Aluminum; Aluminum alloy; Aluminum base alloys; Erbium; Hafnium; Precipitation; Precipitation hardening; Recrystallization; Zirconium
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2015.05.027

A study on the precipitation hardening and recrystallization behavior of dilute Al–Er–Hf and Al–Er–Hf–Zr alloys has been carried out. The results show that both Al–0.045Er–0.18Hf and Al–0.045Er–0.08Zr–0.1Hf alloys can obtain remarkable age strengthening effect and recrystallization resistance. The precipitation hardening rate of Al–0.045Er–0.08Zr–0.1Hf is accelerated compared with that of the Al–0.045Er–0.18Hf alloy due to substituting 0.08at% Zr for Hf, which can be ascribed to the sequential precipitation of solute elements on the basis of the disparity in their intrinsic diffusivities (DEr>DZr>DHf). The peak hardness values for the Al–0.045Er–0.08Zr–0.1Hf are 644MPa and 662MPa after isochronal aging to 450°C and isothermal aging at 350°C for 84h, respectively, which are higher than those of the Al–0.045Er–0.18Hf alloy. The recrystallization temperature of Al–Er–Hf–Zr alloy is 450°C, about 25°C higher than that of the Al–Er–Hf alloy due to the larger f/r ratio of precipitates in Al–Er–Hf–Zr alloys.