微量Er、Zr对Al-1.5Mg合金微观组织和性能的影响

Influence of trace erbium and zirconium on the microstructure and property of Al-1.5Mg alloy

借助OM、XRD和SEM等手段研究了微量Er、Zr元素对Al-1.5Mg合金微观组织和性能的影响。结果表明:合金中除了含有少量的β相(Mg2Al3)和Mg2Si外,绝大部分为铁基相(Al3Fe和Al12Fe3Si);复合添加Er、Zr能促进铁基相析出,实现针状相转化为相对无害的骨骼状相,提高了合金的宏观硬度和加工性能;大部分Er溶解在Al基体中,其余分布在晶界处的Er易吸附固/液界面前沿处的铁等原子,造成成分过冷,从而增加形核率,细化晶粒;Zr几乎都固溶于Al基体中,但有少量Al3Zr粒子形成。

The influence of erbium and zirconium on the microstructure and property of AI-I.5Mg alloy is lnves tigated by optical microscopy（OM）, scanning electron microscopy（SEM） and X-ray diffractometer（XRD）. It is found that the alloy is mostly composed of iron-bearing phase（Al3 Fe and Al12Fe3Si） besides a spot of β-phase （Mg2Al3） and Mg2Si. The combined additions of erbium and zirconium can promote iron-bearing phase precipi tation and induce the transformation from acicular phase to a comparatively harmless skeleton phase, improving the macrohardness and machining performance of Al-1.5Mg alloy effectively. Most erbium exists in the Al ma- trix, and the excess distributing in the grain boundary will absorb iron atoms or others existing in the solid/liq uid interface forward, and result in constitutional supercooling, which increases the nucleation rate and refines grain. Otherwise, zirconium also generally dissolves in the Al matrix, but some Al3Zr particles are observed.