快凝高硅铝合金固溶时效及深冷处理工艺的研究-材料工程专业论文.docx

- - I - 摘 要 本文采用组分为 Al-17Si-1Fe-3.5Cu-2Mn-1Mg-2Ni-1V 的喷射沉积挤压坯，利用 正交试验 的方法， 确定最佳 固溶 +人工 时效工艺 。在此基础上，研究固溶后 进行不 同时间常 温时效 +人工时效处 理及深冷 时间、次 数及顺序对合金显微组织、硬度、 抗拉强度及耐磨性的影响。 结果表明：铸态组织由基体、块状初晶 Si 和长条状及针状第二相组成，沉积态 和挤压态 合金针状 相消失， 第二相呈 颗粒状分 布；经固溶 +时效处理后，部分小尺 寸 β-Si 消失，大尺寸的初晶 Si 尺寸增大，颗粒状第二相更加细小、弥散，合金的 硬度和耐磨性提高；合金经过固溶+72h 常温时效+人工时效处理后，其硬度和耐磨 性较 高。随后 进行固溶 +深冷 +人工时效处理 ，随着深 冷时间的 延长，块状初晶 Si 变得圆钝，颗粒状第二相更加细小、弥散，合金的力学性能得到了很大的提高；调 换人工时效与深冷处理次序后，性能没有提高。并且随着深冷处理次数的提高合金 的力学性能不断提高，但三次性能较二次性能变化不大，所以，本文确定最佳的处 理工艺为 520℃×3h＋深冷处理（24h×2）＋120℃×10h。 关键词：高硅铝合金；固溶时效；深冷处理 ；显微组织；耐磨性 - - II - Abstract In this article, using the spray deposited Al-17Si-1Fe-3.5Cu-2Mn-1Mg-2Ni-1Valloy extrusion billet, and using orthogonal test method, determine the best solid solution treatment and artificial aging process. Base on this, research alloy microstructure and hardness, tensile strength and wear resistance effects of solid solution treatment and different time nature aging and artificial aging ,cryogenic time, and cryogenic count ,the sequence. The results show that: as-cast tissue is comprised of the matrix, the beginning of the crystal Si, long strips and needle the second phase.Needle phase of squeezed state alloy disappeared, the second phase is granular distribution; After solid solution + aging treatment, some of the smaller size β-Si disappear, the larger size Silicon wafer early increase, the granular second phase more small and diffusion, The hardness and wear resistance of alloy improved; After solid solution and 72 h natural aging and artificial aging treatment, its hardness and wear resistance improved. Followed by solid solution and cryogenic and artificial aging treatment, with the the extension of cryogenic time, the beginning of the crystal Si become obtuse, granular second phase become more small and diffusion, the mechanical properties of the alloy improved; Exchange the order of the artificial aging process and cryogenic processing, performance doesnt improve. And as the improvement number of d