AZ91HP镁合金真空激光熔凝晶粒细化  

Grain refinement of AZ91HP magnesium alloy treated by vacuum laser melting

作　　者：高亚丽[1] 王存山[1] 刘红宾[1] 姚曼[2] 

机构地区：[1]大连理工大学三束材料改性国家重点实验室,辽宁大连116023 [2]大连理工大学材料系,辽宁大连116023

出　　处：《材料热处理学报》2006年第1期92-95,共4页Transactions of Materials and Heat Treatment

摘　　要：采用真空激光熔凝技术对AZ91HP镁合金表面进行了细晶强化处理。研究表明:激光熔凝区是由αMg和βMg17Al12相所组成,与原始镁合金相比,βMg17Al12相含量增加,且随着激光扫描速度降低,βMg17Al12相含量增加。熔凝区具有典型的树枝晶形貌特征。由于受微区合金溶液成分和结晶参数不均匀性的影响,二次枝晶间距沿熔凝层深度逐渐增大。增加扫描速度导致熔凝区二次枝晶间距减小,激光熔凝区晶粒细化,有利于提高镁合金的塑性。AZ91HP magnesium alloy was treated by vacuum laser melting. The results show that microstructure of the laser melting zone consists of α-Mg and β-Mg_ 17Al_ 12 phases.The amount of β-Mg_ 17Al_ 12 phase in the melted zone is more than that of the as-received Mg alloy and increases with decreasing of laser scanning speed. The microstructure in the melted zone grows in the form of dentrite shape, and its second dendrite arm spacing increases along the depth of the melted layer due to non-uniformity of melt composition and crystallizing parameters. The second dendrite arm spacing decreases with increasing of scanning speed. The refining of grains is in favor of increasing of magnesium alloy plasticity.

关 键 词：激光熔凝 镁合金 晶粒细化 塑性 

分 类 号：TG166.4[金属学及工艺—热处理] TG156.99[金属学及工艺—金属学]