合金元素对镁合金热裂倾向及粘模性能的影响研究

Study on the effect of alloying elements on the hot tearing tendency and mold adhering properties of magnesium alloys

选择Mg‑1Ca,Mg‑3Al‑0.5Zn和Mg‑3Al‑0.5Zn‑2Ca合金作为研究对象进行热裂倾向及粘模行为实验研究,系统研究了三个合金熔液与SWPH13钢在高温处理后界面层的微观组织。采用Pandat和Thermo‑Calc热力学软件计算了Mg‑3Al‑xCa,Mg‑3Al‑0.5Zn‑xCa和Mg‑3Al‑1Zn‑xCa系合金的相图和部分合金的凝固曲线。计算结果表明,随着Zn元素的加入,合金的凝固区间大幅度增加,提高了镁合金的热裂倾向。Mg‑1Ca合金与SWPH13钢界面处可能形成了CaO化合物。Ca元素的添加加速了Al元素在Mg‑3Al‑0.5Zn‑2Ca/SWPH13钢界面的偏聚,并形成AlFe相,进而导致该合金与模具产生粘连现象。

This study selects Mg-1Ca,Mg-3Al-0.5Zn,and Mg-3Al-0.5Zn-2Ca alloys as the research objects for experimental research on hot tearing tendency and mold adhesion behavior.The microstructures of the interface layer between the three alloy melts and SWPH13 steel after high-temperature treatment are systematically studied.The phase diagrams and solidification curves of Mg-3Al-xCa,Mg-3Al-0.5Zn-xCa,and Mg-3Al-1Zn-xCa alloys are calculated by using Pandat and Thermo-Calc thermodynamics.Combined with the calculation and analysis results,the solidification range of the alloy significantly increases with the addition of Zn element,improving the hot tearing tendency of magnesium alloys.CaO compound may is formed at the interface between Mg-1Ca alloy and SWPH13 steel.The addition of Ca element accelerates the segregation of Al element at the interface of Mg-3Al-0.5Zn-2Ca/SWPH13 steel,forming an AlFe phase,which in turn leads to adhesion between the alloy and the mold.