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利用光学显微镜、X射线衍射仪、扫描电镜研究了0.1%~0.5%的Ca添加量对AZ91镁合金的凝固组织和力学性能的影响。结果表明,添加微量的Ca后,合金的初生相粗化;随着Ca加入量的增加,初生相的尺寸变化不明显,第二相先细化后粗化,转折点为0.4%;加入0.5%的Ca时,发现新相Al2Ca;添加0.4%的Ca后,合金的固液转变温度区间变窄,共晶转变温度升高;随着Ca加入量的增加,力学性能有所提高,当加入0.4%的Ca时,综合力学性能达到最优,其抗拉强度和伸长率分别为261 MPa和14.8%,较未加Ca处理时提高了51%和691%。
The effects of Ca content of 0.1% ~ 0.5% on the microstructure and mechanical properties of AZ91 magnesium alloy were investigated by optical microscope, X-ray diffraction and scanning electron microscope. The results show that the primary phase of the alloy is coarsened with a little Ca addition. The size of the primary phase does not change obviously with the addition of Ca. The second phase is refined first and then roughened. The turning point is 0.4% Of Ca, the new phase Al2Ca was found. After the addition of 0.4% Ca, the solid-liquid transition temperature of the alloy was narrowed and the eutectic transformation temperature was increased. The mechanical properties of the alloy were improved with the addition of Ca, % Of Ca, the comprehensive mechanical properties of the best, the tensile strength and elongation were 261 MPa and 14.8%, compared with no Ca treatment increased by 51% and 691%.