过渡金属Fe,Ni,Sc,Zr对2618铝合金组织和性能的影响

Effects of Transition Metals, Fe, Ni, Sc and Zr, on the Microstructure and Mechanical Properties of 2618 Aluminum Alloy

配制了 3种不同成分的 Al- Cu- Mg- Fe- Ni- (Sc,Zr)实验合金 ,测量了合金在 2 0 0℃的时效曲线及室温、 30 0℃下的拉伸性能 ,采用金相显微镜、扫描电镜 (能谱 )和透射电镜观察了合金不同状态下的显微组织。结果表明 :加入微量 Sc和 Zr后生成的一次 Al3(Sc,Zr)相可明显细化基体晶粒 ,二次析出的 Al3(Sc,Zr)质点有明显的时效硬化效果 ,并且有利于合金中另一强化相 S′(Al2 Cu Mg)更均匀析出 ,从而提高合金的强度 ,Fe,Ni含量的提高会生成难溶的化合物 Al Cu Fe Ni,使固溶体中 Cu含量减少而造成 S′相数量的减少 ,不利于最大限度的提高合金强度。

Three Al Cu Mg Fe Ni (Sc,Zr) alloys with different compositions have been prepared. The age hardening curves of the alloys at 200℃ were measured using vickers hardness, and the tensile properties at both ambient temperature (20℃) and 300℃ were also measured. The microstructures of the alloys were observed using optical microscopy, SEM and TEM. It was found that additions of Sc and Zr to 2618 alloy resulted in a primary Al 3(Sc,Zr) phase which could refine the grain size and a uniform distribution of secondary coherent Al 3(Sc,Zr) particles which had an obvious age hardening effect. The dispersed Al 3(Sc,Zr) precipitates could homogenize the S' phase precipitate such that the strength of the alloy increased at both ambient and elevated temperatures without decreasing ductility. Increasing the Fe and Ni content resulted in an insoluble phase, AlCuFeNi, which produce precipitate strengthening effect and decreased the a mount of S' phase. Thus the mechanical properties, especially the strength, of the alloy with high percent ages of Fe and Ni were not greatly improved.