Dual effect of Cu on the Al3Sc nanoprecipitate coarsening
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第2期
论文作者：Y.H. Gao L.F. Cao J. Kuang J.Y. Zhang G. Liu J. Sun
文章页码：38 - 45
摘 要：It is generally considered that the Al3Sc nanoprecipitates are highly thermal stable, mainly due to quite slow Sc diffusion in the α-Al matrix. In this paper, we demonstrate in an Al-Cu-Sc alloy that the Cu atoms have dual effect on the coarsening of Al3Sc nanoprecipitates. On the one hand, the Cu atoms with high diffusivity tend to accelerate the Al3Sc coarsening, which results from the Cu-promoted Sc diffusion.On the other hand, some Cu atoms will segregate at the Al3Sc/matrix interface, which further stabilizes the Al3Sc nanoprecipitates by reducing the interfacial energy. Competition between these two effects is tailored by temperature, which rationalizes the experimental findings that the coarsening kinetics of Al3Sc nanoprecipitate is greatly boosted at 300℃-overaging while significantly suppressed at 400℃-overaging.
Y.H. Gao1，L.F. Cao2，J. Kuang1，J.Y. Zhang1，G. Liu1，J. Sun1
1. State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University2. International Joint Laboratory for Light Alloys (Ministry of Education), Chongqing University
摘 要：It is generally considered that the Al3Sc nanoprecipitates are highly thermal stable, mainly due to quite slow Sc diffusion in the α-Al matrix. In this paper, we demonstrate in an Al-Cu-Sc alloy that the Cu atoms have dual effect on the coarsening of Al3Sc nanoprecipitates. On the one hand, the Cu atoms with high diffusivity tend to accelerate the Al3Sc coarsening, which results from the Cu-promoted Sc diffusion.On the other hand, some Cu atoms will segregate at the Al3Sc/matrix interface, which further stabilizes the Al3Sc nanoprecipitates by reducing the interfacial energy. Competition between these two effects is tailored by temperature, which rationalizes the experimental findings that the coarsening kinetics of Al3Sc nanoprecipitate is greatly boosted at 300℃-overaging while significantly suppressed at 400℃-overaging.
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