Effect of Trace Element Hf on the Precipitation Process and Recrystallization Resistance of Al-Er-Zr Alloys

Abstract:

Vickers hardness and electric conductivity measurements as well as micro-structure analysis were used to investigate the effects of trace element Hf atoms on the precipitation and recrystallization resistance in Al-Er-Zr alloys. The results of the present study indicated that the behaviors of precipitation process in Al-0.04Er-0.08Zr and Al-0.04Er-0.08Zr-0.05Hf (at. %) alloys are similar. When alloys were annealed at 350 °C for 96h, the nanoscale and coherent Al₃(Er, Zr) and Al₃(Er, Zr, Hf) precipitates form, corresponding to the peak hardness values of 56.2 ± 0.9 (ternary alloy), 58.9 ± 1.5 HV (quaternary alloy), respectively. The higher peak hardness in Al-0.04Er-0.08Zr-0.05Hf alloys mainly benefit from the decomposition of Hf. It was shown that the existence of precipitates could improve the recrystallization resistance obviously. Due to the similar retarding force, recrystallization temperatures of both alloys are almost the same, approximate 450 °C.

• Periodical: Materials Science Forum (Volume 898)
• Pages: 3-8
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.898.3
• Online since: June 2017
• Authors: Tong Hui Liu, Sheng Ping Wen*, Xiao Lan Wu, Hui Huang, Kun Yuan Gao
• Keywords: Al-Er-Zr (Hf) Alloys, Isothermal Ageing, Precipitation, Recrystallization Temperature

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