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采用XRD、高分辨透射电镜及选取电子衍射等手段研究了含铒Al-4.5Mg-0.7Mn-0.1Zr合金中Al3Er相的形成及其微观结构。结果表明Er的含量达到0.4%时,除部分固溶于Al基体中之外,凝固过程中Er开始析出形成初生Al3Er相,初生的Al3Er相以离异共晶的形式形成并分布于晶界处。470℃/20 h均匀化退火过程中,过饱和固溶的Er析出,形成与基体取向相同的共格的L12结构的Al3Er相粒子。粒子的大小为15 nm左右,由于界面能各向异性的结果,粒子的形貌是由低表面能的{100}和{110}晶面围成的近球形的多面体。由于Zr的存在,退火过程中也形成了核壳结构的Al3(ErZr)复合相,其中Er主要分布于复合相粒子的心部,而Zr主要分布于复合相粒子的外部。
The formation and microstructure of Al3Er phase in Er-containing Al-4.5Mg-0.7Mn-0.1Zr alloy were investigated by XRD, high resolution transmission electron microscopy and selected electron diffraction. The results show that when the content of Er reaches 0.4%, except for some solid solution in the Al matrix, Er precipitates and forms primary Al3Er phase during the solidification process. The primary Al3Er phase forms in the form of divorced eutectic and distributes in the grain boundary. During the homogenization annealing at 470 ° C / 20 h, supersaturated solid solution of Er precipitates to form Al3Er phase particles with the same L12 structure as the matrix orientation. The particle size is about 15 nm. Due to the anisotropy of the interface, the morphology of the particles is a nearly spherical polyhedron surrounded by {100} and {110} planes with low surface energy. Due to the existence of Zr, the Al3 (ErZr) composite phase with core-shell structure was also formed during the annealing. Er mainly distributed in the core of the composite phase particles and Zr mainly distributed outside the composite phase particles.