We discovered two distinctive features in the mechanical properties of extruded Mg alloys containing a long-period stacking ordered(LPSO)phase,which are highly desirable for a new class of high-strength,lightweight ma...We discovered two distinctive features in the mechanical properties of extruded Mg alloys containing a long-period stacking ordered(LPSO)phase,which are highly desirable for a new class of high-strength,lightweight materials.First,the Mg/LPSO-extruded alloy shows greater elongation compared to other Mg solid-solution-extruded alloys when a certain high strength is required.Second,the simultaneous achievement of high strength and large elongation in the Mg/LPSO-extruded alloy enhances with a reduction in extrusion speed.In this study,the physical origins of these features were examined,focusing on how changes in the microstructure affect the mechanical properties of the extruded alloys.Our findings clarify that the LPSO phase contributes not only to increased strength but also to enhanced elongation through an increase in the work-hardening rate,a mechanism we termed aanisotropic mechanical property-induced ductilizationo(AMID).Until now,most efforts to improve the ductility of Mg materials have focused on achieving aisotropic mechanical propertieso via grain refinement.Based on our results,we propose an entirely opposite approach:increasing the elongation of Mg alloy by locally enhancing theiraanisotropic mechanical propertieso through the AMID mechanism.Computational analysis further suggests that reducing the diameter of Mg-worked grains should effectively improving elongation in Mg/LPSO alloys with a high volume fraction of Mg-worked grains.展开更多
镁合金具有比强度高、比刚度高、质量轻、切削性能好等优点,在航空航天、汽车制造及医疗服务等领域有着广泛的应用前景,但其绝对强度低,塑性差,限制了镁合金在一些领域的应用。为了改善镁合金综合性能,研究发现在镁合金中按一定比例加...镁合金具有比强度高、比刚度高、质量轻、切削性能好等优点,在航空航天、汽车制造及医疗服务等领域有着广泛的应用前景,但其绝对强度低,塑性差,限制了镁合金在一些领域的应用。为了改善镁合金综合性能,研究发现在镁合金中按一定比例加入稀土元素与过渡族元素后,会出现一种长周期有序堆垛结构(Long Period Stacking Ordered,简称LPSO相),LPSO相具有高硬度、高抗蠕变性能、高弹性模量等优点,能够同时改善合金的强度和塑性,因此,LPSO相引起了广大研究人员的关注。本文综述了稀土镁合金中LPSO相的研究进展,全面分析了LPSO相的类型及原子排布,讨论了LPSO相的形成机制和规律,以及LPSO相对合金性能的影响机制,评述了通过第一性原理对LPSO相晶体结构、弹性模量和LPSO相与层错能间关系的研究,最后对含LPSO相稀土镁合金的未来发展做出展望。展开更多
基金supported by the Japan Science and Technology Agency(JST),CREST(grant number JPMJCR2094)。
文摘We discovered two distinctive features in the mechanical properties of extruded Mg alloys containing a long-period stacking ordered(LPSO)phase,which are highly desirable for a new class of high-strength,lightweight materials.First,the Mg/LPSO-extruded alloy shows greater elongation compared to other Mg solid-solution-extruded alloys when a certain high strength is required.Second,the simultaneous achievement of high strength and large elongation in the Mg/LPSO-extruded alloy enhances with a reduction in extrusion speed.In this study,the physical origins of these features were examined,focusing on how changes in the microstructure affect the mechanical properties of the extruded alloys.Our findings clarify that the LPSO phase contributes not only to increased strength but also to enhanced elongation through an increase in the work-hardening rate,a mechanism we termed aanisotropic mechanical property-induced ductilizationo(AMID).Until now,most efforts to improve the ductility of Mg materials have focused on achieving aisotropic mechanical propertieso via grain refinement.Based on our results,we propose an entirely opposite approach:increasing the elongation of Mg alloy by locally enhancing theiraanisotropic mechanical propertieso through the AMID mechanism.Computational analysis further suggests that reducing the diameter of Mg-worked grains should effectively improving elongation in Mg/LPSO alloys with a high volume fraction of Mg-worked grains.
文摘镁合金具有比强度高、比刚度高、质量轻、切削性能好等优点,在航空航天、汽车制造及医疗服务等领域有着广泛的应用前景,但其绝对强度低,塑性差,限制了镁合金在一些领域的应用。为了改善镁合金综合性能,研究发现在镁合金中按一定比例加入稀土元素与过渡族元素后,会出现一种长周期有序堆垛结构(Long Period Stacking Ordered,简称LPSO相),LPSO相具有高硬度、高抗蠕变性能、高弹性模量等优点,能够同时改善合金的强度和塑性,因此,LPSO相引起了广大研究人员的关注。本文综述了稀土镁合金中LPSO相的研究进展,全面分析了LPSO相的类型及原子排布,讨论了LPSO相的形成机制和规律,以及LPSO相对合金性能的影响机制,评述了通过第一性原理对LPSO相晶体结构、弹性模量和LPSO相与层错能间关系的研究,最后对含LPSO相稀土镁合金的未来发展做出展望。
