中文摘要：

AZ91 的阶段体质和团结小径 ?+? xSb (x ?=? 0， 0.1， 0.5， 1，在 wt%) 合金通过微观结构观察，热分析技术，和热力学的计算的方法被调查。这被发现 AZ91 的非平衡团结微观结构?+? xSb ( x ?=? 0.1 ， 0.5 ， 1 )由 -Mg 矩阵组成， -Mg ₁₇ 艾尔<潜水艇class=“ a-plus-plus ”> 12 阶段，并且金属间化合的复合 Mg <潜水艇class=“ a-plus-plus ”> 3 Sb <潜水艇class=“ a-plus-plus ”> 2 。有不同 Sb 内容的合金的谷物尺寸是不在包含 Sb AZ91 合金显示出谷物精炼的电子 backscattered 衍射技术决定的份量上。热力学的计算在对热分析结果的合理同意，证明 Mg < 潜水艇 class= “ a-plus-plus ” > 3 Sb < 潜水艇 class= “ a-plus-plus ” > 在 -Mg 成核以后的 2 种 阶段形式，这样不可能的行为为 -Mg 的同样异构的原子核树突。而且，在树突连贯点的稳固的部分( f <潜水艇class=“ a-plus-plus ”> s <啜class=“ a-plus-plus ”> DCP )与增加 Sb 内容稍微从热分析减少决定了，它与 Sb 不精制 AZ91 合金的谷物尺寸的事实一致。

英文摘要：

The phase constitution and solidification pathways of AZ91＋xSb（x = 0, 0.1, 0.5, 1, in wt%） alloys were investigated through ways of microstructure observation, thermal analysis technique, and thermodynamic calculation. It was found that the non-equilibrium solidification microstructure of AZ91＋xSb（x = 0.1, 0.5, 1） is composed of a-Mg matrix, b-Mg17Al12 phase, and intermetallic compound Mg3Sb2. The grain size of the alloys with different Sb contents was quantitatively determined by electron backscattered diffraction technique which shows no grain refinement in Sb-containing AZ91 alloy. Thermodynamic calculations are in reasonable agreement with thermal analysis results, showing that the Mg3Sb2 phase forms after a-Mg nucleation, thus impossible acts as heterogeneous nucleus for a-Mg dendrite. Besides,the solid fraction at dendrite coherency point（fDCPs） determined from thermal analysis decreases slightly with increasing Sb content, which is consistent with the fact that Sb does not refine the grain size of AZ91 alloy.