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利用 5k W CO2 激光器对 Al- 5.6wt% Mn合金进行了一系列表面重熔实验 ,并对熔池的形貌和微观组织进行了分析研究。实验结果表明 :重熔区组织较基体组织大大细化 ;随着生长速度的增大 ,重熔区组织由 Al6Mn枝晶向 α(Al) +Al6Mn共晶、α(Al)胞 /枝晶及完全无偏析固溶体转变 ,并对其形成原因进行了分析。熔池中存在的对流和激光扫描过程中工作台运动的不稳定造成了熔池表面波纹状组织和熔池中三维条带状组织的出现。
A series of surface remelting experiments were carried out on Al-5.6wt% Mn alloy with 5kW CO2 laser. The morphology and microstructure of the molten pool were analyzed. The experimental results show that the microstructure of the remelted zone is much refined than that of the matrix. With the increase of the growth rate, the microstructure of the remelted zone changes from Al6Mn to α (Al) + Al6Mn, α (Al) Completely segregation-free solid solution transformation, and its formation causes were analyzed. The presence of convection in the weld pool and the unstable motion of the stage during the laser scanning caused the appearance of three-dimensional ribbon-like structures in the weld pool and in the weld pool.