Twinning behaviors of Mg-Sn alloy with basal or prismatic Mg_2Sn

含基面或柱面Mg_(2)Sn的Mg-Sn合金的压缩孪生行为

The Mg-Sn alloys,with basal or prismatic Mg2Sn laths,were employed to reveal the effect of precipitate orientation on twinning behavior quantitatively.The Mg-5wt.%Sn alloys with basal or prismatic Mg2Sn were compressed to study the twinning behaviors.Subsequently,an Orowan strengthening model was developed to quantitatively investigate the critical resolved shear stress(CRSS)increment of precipitates on twinning.The results revealed that the prismatic precipitates hindered the transfer and growth of tensile twins more effectively compared with the basal precipitates.The decreased proportion of tensile twins containing prismatic Mg2Sn might be attributed to a larger CRSS increment for tensile twins compared with that for basal precipitates.The obvious decreased twinning transfer in the alloy with prismatic Mg2Sn could be due to its higher geometrically necessary dislocation and enhanced CRSS of tensile twins.Notably,the prismatic precipitates have a better hindering effect on tensile twins during compression.

采用含有基面或柱面Mg2Sn相的镁锡合金定量揭示析出取向对孪生行为的影响。对含有基面或柱面Mg2Sn的Mg-5%Sn(质量分数)合金进行压缩,研究其孪生行为。随后,构建一个Orowan强化模型,以定量研究孪生析出相的临界分切应力增量。结果表明,柱面析出相比基面析出相更能有效地阻碍拉伸孪晶的转移和生长。对比含基面析出相的合金,含柱面析出相的拉伸孪晶比例下降归因于拉伸孪晶的临界分切应力增量更大。含有柱面析出相的孪晶转移比率明显降低,归因于该合金中拉伸孪晶的几何必需位错较高和临界分切应力增强。值得注意的是,柱面析出相在压缩过程中对拉伸孪晶具有更好的阻碍作用。