在校生 教职工 考生及访客 校友 EN
第十二期 青年教师论坛

报告题目: Study of the alloying effect on Mg‘s ductility
地    点: 徐祖耀楼313会议室 
时    间: 2019年11月1日(星期五)中午11:30-13:00 
报 告 人: 王乐耘 
  Room temperature ductility is a bottleneck for the application of Mg alloys as structural material. Recent studies have shown that the addition of yttrium (Y) and calcium (Ca) can potentially improve Mg’s ductility. Yet, the underlying mechanism is still unclear. For this presentation, we use both synchrotron X-rays and electron microscopy to understand the issue. In the first work, three dimensional X-ray diffraction (3DXRD) was employed to study slip activity in a rolled Mg-3wt%Y alloy sample that was incrementally loaded by tension. At each load step, 3DXRD data was collected to track the deformation of nearly 1000 grains in the probed volume. By analyzing orientation rotation and stress tensor evolution in those grains, it is possible to identify the activated slip systems and measure their critical resolved shear stress (CRSS) values. The result indicates that Y significantly reduces the CRSS ratio between non-basal slip and basal slip. In the second work, tensile testing of an extruded Mg-0.47 wt.% Ca alloy was conducted inside a scanning electron microscope. EBSD-based slip trace analysis was performed to study in-grain slip activities at different strains. While the majority of the grains were deformed by basal slip, prismatic and pyramidal slip were also frequently observed, and their fractions increased with strain. Schmid factor analysis again indicates a relatively low CRSS ratio between non-basal slip and basal slip in this Mg-Ca alloy. The high ductility in Mg-Y and Mg-Ca alloys are thus attributed to the enhanced activity of non-basal slip.
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