基材晶体取向对激光多层涂覆微观组织的影响

采用镍基合金粉 ,研究了激光多层涂覆过程中基材晶体取向对涂层凝固组织的影响规律。实验发现 ,在适当的工艺条件下 ,若基材表层的晶体取向与合金择优取向相近或一致时 ,可得到与基材晶体取向一致的涂覆层 ,整个涂层中呈现细小、规整且与基材组织连续的定向柱状枝晶 ,仅顶端存在一薄层取向改变的枝晶生长区。而当基材表层晶体取向与合金择优取向不同时 ,涂层中得到的是取向不规则的细小枝晶

Influences of Crystal Orientation of Substrate on Microstructure of Multi-layer Laser Cladding

The influence of the crystal orientation of the substrate on microstructure is investigated by multi layer laser cladding with the powder of nickel base superalloy. With properly organized processing conditions, if the crystal orientation of the surface of the substrate is parallel to the preferred crystal orientation, claddings with the identical crystal orientation to the substrate can be obtained. The cladding layers exhibits fine and regular columnar dendrite except that a thin layer with altered orientation appears at the surface of the external layer. When the experiment was performed on other crystal faces of the substrate, there appears fine and random oriented dendrite.