(沈陽工業(yè)大學 材料科學與工程學院，沈陽 110870)
摘 要: 基于Clyne-Davies模型對Mg-6.5Zn-xY-0.5Zr合金熱裂敏感性進行預測，并通過“T”型熱裂模具對熱裂紋萌生時的溫度和固相量等進行表征，采用掃描電子顯微鏡和X射線衍射等手段，分析析出相對合金熱裂敏感性的影響。結果表明：合金熱裂傾向由大到小的順序為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。組織中含有I相合金的熱裂敏感性要高于含有W相的合金，同時，含有I相和W相合金的熱裂敏感性則高于只含有I相或W相的合金。研究還發(fā)現(xiàn)，易脆區(qū)域ΔTC是反映鎂合金熱裂敏感性的一個重要參數(shù)，合金的ΔTC值越高，合金的熱裂敏感性也越高。
關鍵字: Mg-Zn-Y-Zr合金；熱裂敏感性；析出相；易脆區(qū)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
