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对重力金属型铸造(GPC)和重力砂型铸造(GSC)Mg-3Nd-0.2Zn-Zr(NZ30K)(质量分数,%)合金T6态的显微组织、室温拉伸性能和室温拉压疲劳性能(R=–1)进行对比研究。研究发现,GPC-NZ30K合金晶粒大体呈正态分布,平均晶粒较细小(60μm);GSC-NZ30K合金晶粒分布偏离正态分布,晶粒尺寸大小不均匀且平均晶粒较粗大(70μm)。晶粒细小均匀的显微组织(GPC-NZ30K-T6合金)可以明显提高合金的室温拉伸性能,包括屈服强度(+6.6MPa)、抗拉强度(+43MPa)和延伸率(+2.8%),但对于提高合金的室温拉压疲劳强度(+1.12MPa)作用不明显;平均晶粒略粗大且大小分布不均匀的显微组织(GSC-NZ30K-T6合金)可使NZ30K-T6合金的疲劳性能稳定。
The microstructure, Tensile properties at room temperature and tensile and compressive fatigue properties at room temperature of the T6 state of Gravimetric Metal Casting (GPC) and Gravity Sand Casting (GSC) Mg-3Nd-0.2Zn-Zr (NZ30K) (R = -1) for comparative study. The results show that the grains of GPC-NZ30K alloy are generally normal distribution and the average grain size is small (60μm). The grain distribution of GSC-NZ30K alloy deviates from the normal distribution, the grain size is uneven and the average grain size is coarse (70μm ). Tensile properties at room temperature including the yield strength (+ 6.6MPa), tensile strength (+ 43MPa) and elongation (+ 2.8%) were significantly improved by the microstructure with fine grain size and uniform microstructure (GPC-NZ30K-T6 alloy) , But it did not improve the fatigue strength (+ 1.12 MPa) at room temperature. The average grain size was slightly larger and the microstructure with uneven size distribution (GSC-NZ30K-T6 alloy) could make the fatigue of NZ30K-T6 alloy Stable performance.