Natural-ageing-enhanced precipitation near grain boundaries in high-strength aluminum alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第11期
论文作者：Peipei Ma Chunhui Liu Qiuyu Chen Qing Wang Lihua Zhan Jianjun Li
文章页码：107 - 113
摘 要：Artificial ageing above 165℃ directly after quenching induces the formation of ～50 nm wide precipitatefree zone（PFZ） and ～100 nm wide precipitate-sparse zone（PSZ） consisting of coarse precipitates with a gradient in size and density toward the grain center in a commercial Al-Zn-Mg-Cu alloy. With the grain size decreasing, the fraction of PFZ and PSZ in a grain becomes larger and could even occupy the entire volume of the grain. This undesirable microstructure near the grain boundary is mitigated substantially by natural pre-ageing, leading to an exceptional enhancement of the age hardening potential at elevated temperatures. Natural ageing could fundamentally alter the precipitation near grain boundary, and is a promising method to optimize the precipitation hardening in high strength aluminum alloys with unconventionally small grains.
Peipei Ma1，Chunhui Liu1,2，Qiuyu Chen2，Qing Wang1,2，Lihua Zhan1,2，Jianjun Li2
1. Light Alloy Research Institute of Central South University, State Key Laboratory of High-Performance Complex Manufacturing2. School of Mechanical and Electrical Engineering, Central South University
摘 要：Artificial ageing above 165℃ directly after quenching induces the formation of ～50 nm wide precipitatefree zone（PFZ） and ～100 nm wide precipitate-sparse zone（PSZ） consisting of coarse precipitates with a gradient in size and density toward the grain center in a commercial Al-Zn-Mg-Cu alloy. With the grain size decreasing, the fraction of PFZ and PSZ in a grain becomes larger and could even occupy the entire volume of the grain. This undesirable microstructure near the grain boundary is mitigated substantially by natural pre-ageing, leading to an exceptional enhancement of the age hardening potential at elevated temperatures. Natural ageing could fundamentally alter the precipitation near grain boundary, and is a promising method to optimize the precipitation hardening in high strength aluminum alloys with unconventionally small grains.
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