激光修复GH4169高温合金的组织与力学性能

Microstructure and Mechanical Properties of Laser Repaired GH4169 Superalloy

研究了激光修复GH4169高温合金的显微组织与拉伸性能。结果表明：激光修复GH4169高温合金沉积态组织为沿沉积方向外延连续生长的柱状晶,在枝晶间析出了大量Laves相。靠近修复界面的锻件基材在热影响下发生了完全固溶,呈现为300μm宽的白亮带。经双级时效（DA）处理后,Laves相颗粒发生部分固溶。DA状态下合金断口形貌与沉积态相似,形成了方向性明显的沿柱状树枝晶排布的韧窝以及无方向性等轴的韧窝形貌,同时在断口上都存在大量的二次裂纹。所有拉伸试样断裂位置在修复区并且距离修复界面2~3mm。

Microstructure and mechanical properties of laser forming repaired GH4169 were investigated in this paper.The results showed that the microstructure of as-deposited samples was columnar dendrite which grew epitaxially along the deposition direction from the substrate.A mass of block Laves phase precipitated between dendrites.Wrought substrate near the repair interface occurred completely solid solution on account of heat effect of laser power input.The zone presented a bright white region with a width of about 300 μm under an optical microscope.When the LFR GH4169 alloy samples were treated with two-stage aging treatment,compared with as-deposited samples,Laves particles occurred partially solid solution.The Nb concentration in Laves of as-deposited samples was the same as that of DA-treated samples.The comprehensive mechanical properties of the LFR GH4169 alloy were comparative with wrought standard.The tensile fracture surface of LFR samples after DA presented the feature of dimples along the row arrangement of columnar dendrites and equiaxed dimples regularly arranged,which was similar to that of the as-deposited samples.A large number of secondary cracks can be observed on the fracture surfaces.All of the fractures happened in the repaired zone with the distance of 2-3 mm to repair interface.