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利用激光熔覆成形技术制备出平整无变形的镍基合金样品,对显微组织中的层生长模式、晶粒生长模式,重熔情况以及一些缺陷等凝固组织的特征进行了详细分析。结果表明层的形状主要取决于激光功率和粉末熔化状况,显微组织以细长的柱状晶为主。为使层与层之间具有良好的冶金结合,每层的重熔区域必须保持一定的厚度。激光功率过低时组织中易形成气孔,而成形件的卷曲现象可以通过预热等方法加以解决。
The flat and non-deformable Ni-based alloy samples were prepared by laser cladding forming technique. The characteristics of the solidified structure such as layer growth mode, grain growth mode, remelting condition and some defects in the microstructure were analyzed in detail. The results show that the shape of the layer depends mainly on the laser power and the melting state of the powder, and the microstructure is dominated by slender columnar crystals. In order to have a good metallurgical bond between the layers, the remelting area of each layer must be of a certain thickness. When the laser power is too low, pores are easily formed in the tissue, and the curling phenomenon of the formed part can be solved by methods such as preheating.