【摘要】 采用直冷半连续铸造法制备了三种不同成分的Al-Zn-Mg-(Sc)-(Er)合金材料。利用金相显微镜、扫描电镜和透射电镜进行微观组织观察,采用差热分析仪测试相变转变温度,测试了硬度、拉伸性能并利用扫描电镜进行断口分析。结果表明:Al-8.5Zn-1.5Mg-0.1Zr合金中添加0.1%Sc+0.1%Er的晶粒细化效果最好,室温拉伸性能最佳,抗拉强度、屈服强度和伸长率分别可达585 MPa、566 MPa和8.3%;添加0.2%Er元素(0.1%Er等量替代0.1%Sc)的合金的晶粒细化效果和室温拉伸性能均明显差于Al-8.5Zn-1.5Mg-0.1Zr-0.1Sc-0.1Er合金;而添加0.4%Er元素(0.3%Er过量替代0.1%Sc)与添加0.1%Sc+0.1%Er元素对于Al-8.5Zn-1.5Mg-0.1Zr合金在晶粒细化和室温拉伸性能方面带来的增益效果较为接近,但较高含量的Er元素添加容易在合金内部形成偏聚的现象。更多还原

【Abstract】 Three different compositions of Al-Zn-Mg-(Sc)-(Er) alloy were produced by the hot-top semi-continuous DC casting technology. Microstructure of the alloy and the temperature of phases transformation were investigated by optical microscopy(OM), scanning electron microscope(SEM), transmission electron microscopy(TEM)and differential scanning calorimetry(DSC). Hardness and tensile properties of the alloy was measured, and the fracture morphology was observed by SEM. The result showed that the grain size of Al-8.5Zn-1.5Mg-0.1Zr-0.1Sc-0.1Er alloy was the smallest, and the tensile properties was the best at the same time with the tensile strength, yield strength and elongation of 585 MPa, 566 MPa and 8.3%, respectively, as compared to those of Al-8.5Zn-1.5Mg-0.1Zr alloy with 0.2%Er. The effect of adding 0.4%Er or 0.1%Sc+0.1%Er in the Al-8.5Zn-1.5Mg-0.1Zr alloy on the grain size and tensile property was almost same. However, adding too much Er element easily caused the micro clustering of Er element in the alloy.更多还原