【作者】 庞铭； 谭建松； 王建平； 吴波； 解志民； 郑彩云；

【Author】 PANG Ming1, TAN Jian-song1, WANG Jian-ping1, WU Bo1, JIE Zhi-min1, ZHENG Cai-yun2 (1. Substation China North Engine Research Institute,Langfang 065000, China; 2. Chinese Academy of Sciences , Beijing 100190, China)

【机构】 中国北方发动机研究所分所； 中国科学院力学研究所；

【摘要】 研究了额定功率为3kW的Nb:YAG激光焊接K418与42CrMo异种金属,通过光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、能谱仪(EDS)分析了焊缝接头组织和成分。结果表明,焊缝与母材交界组织为具有一定方向的枝晶组织,焊缝中心为等轴晶。由于激光焊接熔池的非平衡凝固,焊缝枝晶间弥散分布着颗粒状的Laves相、针状的MC碳化物和8字形的γ′。Laves相具有熔点低、硬和脆的特点,在焊缝区域常成为裂纹萌生和扩展的地方。为了提高焊缝的力学性能,需要优化工艺参数,抑制Laves的形成。更多还原

【Abstract】 Experiments of laser welding cast Ni-based superalloy K418 and alloy steel 42CrMo dissimilar metal were conducted using a 3 kW continuous wave (CW) Nd: YAG laser. Microstructure of the welded seam was characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM) and energy dispersive spectrometer (EDS).Results show that the microstructure of interface between welded seam and base metal is mainly composed of a certain direction dendrites. Equiaxial crystal were observed in the center of weld seam .Moreover,needle MC carbide and particles laves and eight γ′ is observed in the interdendritic regions due to non-equilibrium solidification of melt pool..Laves phase of low melting point and brittle property is detrimental to weld mechanical properties as it aids in easy crack initiation and propagation.It is necessary to inhibit laves phase for improving weld mechanical properties by optimal welding parameters.更多还原