摘要
The precipitation hardening behavior in dilute Al-Yb alloys upon annealing at different temperatures was investigated to shed light on the mechanism of micro-alloying element in aluminum alloys. When aging at different temperatures, the samples showed their corresponding peak hardness in the range of 400-416 MPa due to the precipitation of Al3Yb with L 12 crystal structure. The coarsening kinetics of the Al3Yb precipitates obeyed the LSW theory, which indicated that the coarsening process was controlled by the diffusion of Yb. The coherence between Al3Yb particles and matrix was maintained until the particle size reached 11 nm. When the particle size increased to about 2 nm, the shearing mechanism started to change to Orowan mechanism.
研究了稀二元Al一Yb合金在不同时效温度下的析出强化行为。结果表明，在时效过程中析出了细小、弥散的L12结构Al3Yb相，时效析出所能达到的峰值硬度为400～416MPa，各温度的峰值硬度比较接近。L12结构的Al3Yb析出相的粗化动力学遵循LSW理论，表明粗化由溶质原子扩散控制。当Al3Yb析出相的半径小于11nm时其与基体保持共格关系，大于11nm时开始出现半共格现象。当析出相的半径小于2nm时，时效强化的机理是位错切割机制，大于2nm时则主要为位错绕过的Orowan机制。
基金
Project(2013AA031301)supported by Hi-tech Research and Development Program of China
Project(S2013ZR0611)supported by the National International Scientific and Technological Cooperation Program of China
