聚焦光束粉末堆焊层的凝固组织形貌及其形成机理

研制了由光束发生器、聚焦系统、旋转气流送粉器、工作台组成的聚焦光束堆焊系统。堆焊层中凝固组织形态以及树枝晶生长方向取决于熔池凝固过程中的传热过程。45钢表面的Ni基合金堆焊层的微观组织呈现树枝晶形态,树枝晶沿堆焊方向前倾生长,堆焊层金属与母材金属间形成平面晶带,平面晶带依附于母材半熔化区联生结晶长大。

Formation Mechanism and Morphology of Solidification Structure in a Light Beam Powder Surfacing Layer

The light beam surfacing system was developed which consisted of light beam generator, optical focusing system, powder-feed apparatus and work table. The morphology of the solidification structure and the growth direction of the dendrite depended on the heat transfer during the solidification process of the molten pool. The microstructure of Ni-based surfacing layer upon 1045 steel was the dendrite that grew forward along the direction of surfacing. The Planar crystal strip tbrmed between the surfacing layer and the base metal which epitaxially grew from the partially fusion zone of the base metal.