(沈阳工业大学 材料科学与工程学院，沈阳 110870)
摘 要: 基于Clyne-Davies模型对Mg-6.5Zn-xY-0.5Zr合金热裂敏感性进行预测，并通过“T”型热裂模具对热裂纹萌生时的温度和固相量等进行表征，采用扫描电子显微镜和X射线衍射等手段，分析析出相对合金热裂敏感性的影响。结果表明：合金热裂倾向由大到小的顺序为Mg-6.5Zn-2Y-0.5Zr、Mg-6.5Zn-0.5Y-0.5Zr、Mg-6.5Zn-1Y-0.5Zr、Mg-6.5Zn-4Y-0.5Zr和Mg-6.5Zn-6Y-0.5Zr。组织中含有I相合金的热裂敏感性要高于含有W相的合金，同时，含有I相和W相合金的热裂敏感性则高于只含有I相或W相的合金。研究还发现，易脆区域ΔTC是反映镁合金热裂敏感性的一个重要参数，合金的ΔTC值越高，合金的热裂敏感性也越高。
关键字: Mg-Zn-Y-Zr合金；热裂敏感性；析出相；易脆区域
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:The hot tearing susceptibility of Mg-6.5Zn-xY-0.5Zr alloys was predicted based on the Clyne-Davies model, the temperature and solid fraction of hot crack initiation were characterized by the “T” type hot tearing mold. The effect of the precipitated phase on the hot tearing susceptibility of alloys was analyzed by X-ray diffraction and scanning electron microscopy. The results show that the hot tearing susceptibility of investigated alloys are listed in descending order of Mg-6.5Zn-2Y-0.5Zr, Mg-6.5Zn-0.5Y-0.5Zr, Mg-6.5Zn-1Y-0.5Zr, Mg-6.5Zn-4Y-0.5Zr, Mg-6.5Zn-6Y-0.5Zr. The hot tearing susceptibility of the alloys containing I phase is higher than that of alloys containing W phase, and the hot tearing susceptibility of the alloys containing I phase and W phase is higher than that of alloys containing only I phase or W phase. It is also found that the vulnerable region ΔTC is an important parameter to characterize the hot tearing susceptibility of the magnesium alloys. The higher of the ΔTC value is, the higher of the hot tearing susceptibility is.
Key words: Mg-Zn-Y-Zr alloy; hot tearing susceptibility; precipitated phase; vulnerable region
