缺口冲击韧性是金属材料应用的一个重要动态性能指标.本文针对AZ31镁合金板材,在-80～260℃范围内,进行了Charpy Ⅴ型缺口冲击试验,测试了其缺口冲击韧性随温度变化的规律,试验结果表明:在120～160℃范围内,AZ31镁合金存在韧脆转变现象,根据能量标准和延性标准测得的韧脆转变温度均为140℃.并通过SEM手段对-80℃、0℃、80℃、140℃、200℃以及260℃等典型温度下的冲击断口形貌进行了比较分析,结果表明在-80～80℃范围内断口为准解理形貌;80～200℃范围内断口形貌是准解理+韧窝;200～260℃温度范围内断口是韧窝形貌.%Notch impact toughness is an important dynamic property for applications of metallic materials. Charpy V type notch impact test of AZ31 magnesium alloy was carried out from -80 ℃ to 260 ℃,and the relationship between notch impact toughness and temperature was tested. It is indicated that AZ31 magnesium alloy occurs ductile-brittle transition phenomena in the temperature range from 120 ℃ to 160 ℃,and the ductile-brittle transition temperature is about 140 ℃ according to both the energy criterion and ductility criterion. Moreover, scanning electron microscopy (SEM) micrographs of the fracture surfaces at -80 ℃, 0 ℃, 80 ℃, 140 ℃, 200 ℃ and 260 ℃ were comparatively analyzed, the results show that the fracture surfaces present quasi-cleavage patterns when temperature ranges from -80 ℃ to 80℃, quasi-cleavage and dimple patterns from 80 ℃ to 200 ℃ and many dimple patterns are found on fracture surfaces from 200 ℃ to 260℃.
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