Controlled in situ SEM tensile tests have been carried out between 200 and 300 °C at a constant strain rate of 5.10^-5 s^-1 to investigate the effect of temperature on deformation mechanisms operating in an Mg–3Al–1Zn (AZ31) Mg-alloy. Fiducial microgrids deposited using electron beam lithography are used to evidence grain boundary sliding as well as to determine the spatial strain heterogeneities as a function of temperature. Dislocation creep and grain boundary sliding coexist between 200 and 300 °C but their respective activity varies significantly as shown by the strain rate sensitivity value m which is about 0.2 at 200 °C but about 0.5 at both 250 and 300 °C. In addition, grain boundary sliding becomes predominant at 250 and 300 °C whereas its occurrence is relatively limited at 200 °C. Slip trace analysis shows that at 200 °C prism and pyramidal <c+a> slip already exhibit a great activity. Spatial strain heterogeneities determined by digital image correlation (DIC) based on microgrid displacements develop during the early stage of plastic deformation and persist at larger strains. It is shown that the strain in the vicinity of grain boundaries intensifies when the temperature rises from 200 to 300 °C while the core of grains accommodates less deformation in agreement with the fact that grain boundary sliding is predominant at 250 and 300 °C.

在200至300°C之间以5.10 ^-5 s ^-1的恒定应变速率进行了受控的原位SEM拉伸试验，以研究温度对Mg-3Al-1Zn（AZ31）Mg-合金。使用电子束光刻技术沉积的基准微网格被用于证明晶界滑动以及确定空间应变异质性随温度的变化。位错蠕变和晶界滑动在200至300°C之间共存，但它们各自的活动变化很大，如应变率敏感性值m所示。在200°C时约为0.2，而在250和300°C时约为0.5。此外，晶界滑动在250和300°C时占优势，而在200°C时则相对有限。滑移痕迹分析表明，在200°C时，棱柱形和金字塔形<c + a>滑移已经显示出很大的活性。由数字图像相关性（DIC）基于微网格位移确定的空间应变异质性在塑性变形的早期阶段发展，并在较大应变下持续存在。结果表明，当温度从200升至300°C时，晶界附近的应变会增强，而晶核的变形较小，这与250和300°C时晶界滑动为主的事实是一致的。