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铸态的Mg-9.96Zn-2.10Y(质量分数,下同)合金在2、4、6GPa高压下进行凝固并分别对铸态、2GPa、4GPa下凝固的合金进行热压缩,然后借助OM、SEM、XRD和显微硬度计对其组织、相组成和性能进行分析测试。结果表明,随着凝固压力增大,合金组织由铸态的树枝晶转变成细小的柱状晶再到胞状晶,中间相也由分布不均匀且相互连接的网络状转变成细小、均匀的弥散状。XRD结果显示了不同凝固条件下的合金相组成不同;合金的硬度值是先增大再减小,4GPa下凝固的合金硬度达到峰值。热压缩的应力-应变曲线表明,铸态、2GPa、4GPa合金的峰值应力依次增大,但其对应的应变量却依次减小,热压缩后4GPa压力的合金组织最细小、均一。
The as-cast Mg-9.96Zn-2.10Y (mass fraction, the same below) alloy was solidified under high pressure of 2, 4 and 6 GPa, respectively, and the alloy solidified at 2GPa and 4GPa was hot-compressed. XRD and microhardness tester were used to analyze the microstructure, phase composition and properties. The results show that with the increase of the solidification pressure, the alloy structure changes from as-cast dendrites to fine columnar crystals to cellular crystals, and the mesophase changes from a network with uneven distribution and interconnection to a fine and uniform dispersion . The results of XRD showed that the phase composition of the alloy under different solidification conditions was different. The hardness of the alloy first increased and then decreased, and the hardness of alloy solidified at 4GPa reached the peak value. The stress-strain curves of hot compression show that the peak stresses of as-cast, 2GPa and 4GPa alloys increase in order, but the corresponding strain decreases in turn, and the alloy with 4GPa pressure is the smallest and uniform after hot compression.