A357铝合金半固态流变压铸成形组织工艺研究  

Study on Microstructure-processing Relationship of a Semi-solid Rheo-diecasting A357 Aluminum Alloy

作　　者：杨柳青[1] 康永林[1] 张帆[1] 陶涛[1] 丁瑞华[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《材料工程》2009年第6期64-66,72,共4页Journal of Materials Engineering

基　　金：国家重点基础研究发展计划(973计划)项目(2006CB605203);国家高技术研究发展计划(863计划)项目(2006AA03Z115)

摘　　要：介绍了一种实验室自行研制的半固态浆料制备及流变成形设备,该设备主要由熔炼炉、剪切制浆装置、温度控制系统、气体保护装置、连接装置及压铸系统组成。研究了在不同工艺条件下通过该流变成形设备制备A357铝合成形件的组织特点。探讨了半固态流变压铸过程中的凝固行为。实验结果表明:通过该实验设备能有效的消除普通铸造中出现的粗大树枝晶,制备出细小、圆整且均匀分布的半固态组织,而且能消除铸件中的气孔和显微疏松。剪切速率的增大有利于半固态A357铝合金初生1α-Al晶粒的形成及球化。在半固态浆料制备过程中,以初生α1-Al晶粒的形成为主;在随后的压铸过程中,则以较为细小的二次凝固α2-Al晶粒的形成为主。A semi-solid preparing and rheomoulding apparatus which self-developed for light alloys in laboratory is introduced. It mainly consists of a melting furnace, a shearing system with two relative-rotating conical barrels, a central temperature control unit, gas protection system, conveying appliance and a die-casting system. Microstructure-processing relationship of A357 aluminum alloy obtained by the apparatus was investigated. Solidification behavior of the semi-solid rheo-diecasting processing was discussed. The results show that the apparatus is capable of eliminating coarse dendrites, and producing small and spherical solid particles uniformly distribution in a eutectic matrix. In addition, the process can eliminate entrapped gas and reduce fine shrinkage pores in the specimens as well. The primary α1-Al particles will become rounding with the increase of shear rate. During the SSM slurry preparing, the primary α1-Al particles is formed firstly. Secondary solidification of the slurry takes place in the die-casting process.

关 键 词：A357铝合金 半固态 流变压铸 组织工艺 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249.2[金属学及工艺—金属材料]