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.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2006年第1期92-95,共4页
Transactions of Materials and Heat Treatment
关键词
激光熔凝
镁合金
晶粒细化
塑性
laser melting
magnesium alloy
grain refinement
plasticity
