激光成形修复K418高温合金的微观组织与硬度

Microstructure and Microhardness of Laser Forming Repaired K418 Superalloy

采用激光立体成形技术对K418合金进行了成形修复,研究了其微观组织与硬度。结果表明,修复K418合金由基体区、热影响区与激光修复区组成,分别由形貌、大小及数量不同的γ-FeCr0.29Ni0.16C0.06基体相、γ′-Ni3Al相及碳化物相组成;铸造基体区与修复区呈紧密的冶金结合,修复区组织呈沉积方向外延生长的柱状晶及连续的层带状结构。在同一沉积层中由于存在粗大树枝晶区与细小树枝晶区而具有不同的硬度。铸造基体区、热影响区与激光修复区的平均硬度值(HV)分别为432.4、499.4、490.6。

The microstructure and microhardness of laser forming repaired(LFRed) K418 superalloy were investigated.The results reveal that the LFRed sample can be divided into cast substrate zone(CSZ),heat-affected zone(HAZ)and laser repaired zone(LRZ).The microstructures with different morphology,size and number are composed ofγ-FeCr0.29Ni0.16C0.06matrix phases,γ′-Ni3Al phases and MC carbides phases.The LFRed sample presents a compact metallurgical bonding between CZS and LRZ.The LRZ presents columnar dendrites which grew epitaxially along the direction of deposition and a consecutive layer structure.There are difference in microhardness because of difference in grains size at the same deposition layer.The average microhardness of CSZ,HZA and LRZ reach 432.4,499.4 and 490.6HV,respectively.