Improved stress relaxation stability of a heat-resistant Al-Cu-Mg-Ag alloy with good mechanical properties by a pre-annealing/solution-aging treatment

• Published in: Journal of alloys and compounds 2023-10, Vol.961, p.171145, Article 171145
• Main Authors: Zhao, Ziyao, Xiao, Namin, Zhang, Zhihao, Wang, Zhilei
• Format: Article
• Language: English
• Subjects: Al-Cu-Mg-Ag alloy; Microstructure; Pre-annealing; Stress relaxation stability
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.171145

Good stress relaxation stability enables heat-resistant aluminum alloys to serve well at high temperatures. From the viewpoint of simultaneous regulation of microstructure and precipitates, a deliberate pre-annealing (200–400 ℃) followed by solution-aging (T6) treatment was proposed to improve the stress relaxation stability of an Al-Cu-Mg-Ag heat-resistant aluminum alloy in this work. A peak effect on the stress relaxation stability was found with a pre-annealing temperature of 325 ℃, which is associated with larger-sized grains and finer-sized precipitates of the alloy. This interesting peak phenomenon is attributed to a good balance of recrystallization and precipitation. Moreover, the regulated microstructure surprisingly assisted the 325 ℃ pre-annealing+T6 treated alloy with good tensile properties. The proposed heat treatment method provides a route for developing high-performance heat-resistant aluminum alloys. [Display omitted] •A heat-resistance Al alloy was prepared via pre-annealing/solution-aging treatment.•Regulation of grains and precipitates improved stress relaxation stability.•The alloy showed higher tensile properties than the alloy without pre-annealing.