快速凝固Al-Cr-Zr-Fe 合金的微观组织和性能

采用单辊旋淬法制备Al-4Cr-4Zr-2Fe(质量分数, %)合金薄带。利用透射电镜、X射线衍射、能谱分析技术研究了合金急冷态和退火态的显微组织, 测定了合金的显微硬度。结果表明:在快凝Al-Cr-Zr合金中添加铁元素可增加合金的室温和高温性能, 快速凝固Al-4Cr-4Zr-2Fe合金所形成的过饱和固溶体α-Al在400 ℃左右形成Ll₂-Al₃Zr和Al₄(Cr, Fe)相, 产生明显的沉淀硬化效应, 其中, Ll₂-Al₃Zr相为主要强化相。在Al-4Cr-4Zr-2Fe快凝组织中, 发现一种方形Al-Zr相, 该相作为形核核心, 位于等轴晶α-Al中央。

Microstructure and Property of Rapidly Solidified Al-Cr-Zr-Fe Alloy

Rapidly solidified Al-4Cr-4Zr-2Fe alloy (mass, %)was prepared by melt spinning.As-quenched and as-annealed microstructures were inverstigated by TEM, XRD and EDS analysis.The microhardness of the alloy was measured.The results show that addition of elemental Fe in Al-4Cr-4Zr alloy can increase the microhardness of the alloy at room and elerated temperature.At about 400 ℃, the α-Al supursaturated solid solution of the rapidly solidified Al-4Cr-4Zr-2Fe alloy formed Ll₂-Al₃Zr and Al₄(Cr, Fe)precipitates, indicating a marked precipitate-hardening response.The Ll₂-Al₃Zr phasewas a main strengthening phase.A cuboidal phase with Al-Zr composition was found in as-quenched structure of the rapidly solidified Al-4Cr-4Zr-2Fe alloy.The cuboidal phase, lying in the centre of peritectic α-Al, acts as a nuleus to form crystals.