Zr对电磁连续铸造Al-4.0Cu-1.4Mg-0.5Mn 合金铸态组织与力学性能的影响

采用金相、硬度测量、拉伸试验、扫描电镜,XRD等测试手段,研究了Zr对电磁连续铸造Al-4.0Cu-1.4Mg-0.5Mn系高强铝合金铸态下显微组织和力学性能的影响。结果表明,添加微量Zr可明显细化合金铸态组织,且可显著提高合金力学性能,其作用机理主要为Al3Zr造成的细晶强化和弥散强化作用;含Zr的合金在室温下比不含Zr的合金宏观硬度提高3.91%,抗拉强度提高3.90%,屈服强度提高4.82%,伸长率提高48.66%;合金的断裂方式均属韧性断裂,但韧窝分布不均匀,在韧窝中心及边缘处都有第二相。

Effect of Zr on the Cast Microstructure and Mechanical Properties of Al-4.0Cu-1.4Mg-0.5Mn Alloy by Electromagnetic Continuous Casting

The effects of Zr on the cast microstructure and mechanical properties of Al-4.0Cu-1.4Mg-0.5Mn high strength aluminum alloy by electromagnetic continuous casting were studied by using optical microscope, hardness measurement, tensile test, scanning electron microscope and XRD etc. The results show that Zr can remarkably improve the properties of the Al-4.0Cu-1.4Mg-0.5Mn alloys. The strengthening mechanism is considered as fine grain strengthening and dispersion strengthening; The macrohardness of the alloy with Zr increases by 3.91%, the tensile strength and the yield strength of alloy with Zr can raise about 3.90% and 4.82% respectively and elongation improves by 48.66% compared with that of the alloy without Zr in as-cast state. The alloy with Zr expresses ductile fracture mechanism, but the dimples are nonuniform distribution, there are some second-phases in the edge and center of dimple.