Deformation induced solute segregation and G.P. zone formation in Mg-Al and Mg-Zn binary alloys
Deformation induced solute segregation and G.P. zone formation in Mg-Al and Mg-Zn binary alloys
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DOI：
10.1016/j.scriptamat.2022.114924
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发表时间：
2022
影响因子：
6
通讯作者：
T. Sasaki;J. Lin;Peng Yi;Z.H. Li;S. Prameela;A. Park;E. Lipkin;Andrew Lee;M. Falk;T. Weihs;K. Hono
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文献类型：
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作者：
T. Sasaki;J. Lin;Peng Yi;Z.H. Li;S. Prameela;A. Park;E. Lipkin;Andrew Lee;M. Falk;T. Weihs;K. Hono
吉尼尔·普雷斯顿(G.P.)Zones在变形镁合金中产生诱人的机械性能。然而，有报道称，在数量有限的镁合金中有G.P.区的析出。在这里，我们报道了在150℃等通道转角挤压后，在Mg-9Al和Mg-5Zn(wt.%)合金中形变诱导的G.P.区析出。虽然挤压导致形成由未再结晶和再结晶区组成的双峰晶结构，但原子探针断层扫描显示这两个区域都有高密度的G.P.区。此外，分子动力学/蒙特卡罗混合模拟表明，Al和Zn溶质原子对挤压过程中过剩空位形成的空位团簇的吸引可能是G.P.区形成的主要驱动力。这种实验和计算的结合表明，对原子尺度缺陷的战略控制可以产生远离平衡的新的微观组织，从而为强化严重变形的镁合金提供了一种创新的方法。
A dispersion of Guinier Preston (G.P.) zones yields attractive mechanical properties in wrought magnesium alloys. However, the precipitation of G.P. zones has been reported in a limited number of Mg alloys. Here, we report deformation-induced G.P. zone precipitation in Mg-9Al and Mg-5 Zn (wt.%) alloys following equal channel angular extrusion at 150 °C. While the extrusion leads to the formation of a bimodal grain structure consisting of unrecrystallized and recrystallized regions, atom probe tomography reveals a high number density of G.P. zones across both regions. Furthermore, hybrid molecular dynamics/Monte Carlo simulations suggest that the attraction of Al and Zn solute atoms to vacancy clusters formed from excess vacancies during extrusion could be the major driving force for the G.P. zone formation. This combination of experiments and computations demonstrates that strategic control of atomic-scale defects can generate novel, far from equilibrium, microstructures, thereby providing an innovative approach to strengthening severely deformed Mg alloys.