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采用常规和高分辨电镜研究了时效AZ91镁铝合金中 2种形态γ Mg17Al12 析出相的HCP/BCC相界面结构。发现第一类析出相的惯习面 (0 0 0 2 ) α∥ { 330 } γ 以及与其对接的另外 2组主要晶面的面间错配度都很小 (4%和2 % ) ,因此界面能较小 ;而第 2类析出相的惯习面 (0 110 ) α∥ (330 ) γ 以及与其对接的另一组主要晶面的面间错配度都较大 (11%和 15 % ) ,因此界面能较大。从界面能和相变应变两方面讨论了各类析出相析出密度差别的原因 ,提出了改变析出密度、提高镁铝合金时效强化效果的可能途径
The HCP / BCC interphase structure of two morphologies of Mg17Al12 precipitates in aged AZ91 magnesium alloy was studied by conventional and high-resolution electron microscopy. It is found that the mismatch between the surface (0 0 0 2) α∥ {330} γ of the first precipitation phase and the other two main planes interfacing with it is very small (4% and 2%) And the interfacial misorientation between the α (330) γ and the interlaminar faces of the second group of precipitates is larger (11% and 15%, respectively) ), So the interface can be larger. The reasons for the difference in precipitation density of various precipitation phases are discussed from the aspects of interfacial energy and transformation strain, and the possible ways to change the precipitation density and improve the aging strengthening effect of Mg-Al alloy are proposed