Zr58Nb2.76Cu15.46Ni12.74Al10.34Y0.5非晶合金激光焊接接头微观结构及显微硬度表征

目的 探究激光焊接参数对非晶合金焊接接头的组织演变、焊缝成形、晶化程度等的影响规律，以及控制接头晶化的有效途径。方法 采用碟片激光器对Zr58Nb2.76Cu15.46Ni12.74Al10.34Y0.5非晶合金进行激光焊接，对比分析不同激光功率下，焊接速度对接头熔宽和晶化组织形成的影响规律，并对接头各区域微观组织特征及硬度分布进行测试分析。结果 非晶合金激光焊接接头成形良好，焊缝区组织整体为非晶，存在少量纳米晶，热影响区则发生明显晶化现象。当功率为1 200 W时，逐渐提升焊接速度，接头晶化率由28.9%降到13.76%，熔宽由2.04 mm收窄至1.8 mm。当功率为4 500 W时，逐渐提升焊接速度，接头晶化率从9.99%下降为7.47%，焊缝晶化现象消失，熔宽从1.10 mm降到0.98 mm。结论 调节关键焊接参数可实现焊缝区晶化现象的消失，使热影响区晶化程度降低。大激光功率以及高焊接速度更有利于形成熔宽小、晶化程度低的焊接接头。焊缝区硬度与母材基本保持一致，热影响区由于发生晶化，硬度最高。

Microstructure and Microhardness Characterization of Zr58Nb2.76Cu15.46Ni12.74Al10.34Y0.5 Amorphous Alloy Laser Welded Joint

This paper aims to explore the effect of laser welding parameters on the microstructure evolution, weld forming and crystallization degree of amorphous alloy welded joint, and the effective way to control the crystallization of the joint. In this paper, Zr58Nb2.76Cu15.46Ni12.74Al10.34Y0.5 amorphous alloy was welded by the disc laser beam. The effect of welding speed on the fusion width and crystallographic structure of the joint under different laser powers was compared and analyzed, and the microstructures and microhardness distributions of each region in the welded joints were tested and analyzed. The results show that the amorphous alloy laser welded joint is well-formed, the microstructure of the weld zone is amorphous with a small amount of nanocrystalline, and the heat-affected zone has obvious crystallization. When the power was 1 200 W, the welding speed was gradually increased, the joint crystallization rate decreased from 28.9% to 13.76%, and the melting width narrowed from 2.04 mm to 1.8 mm. When the power was 4 500 W, the welding speed was gradually increased, the joint crystallization rate decreased from 9.99% to 7.47%, the weld crystallization phenomenon disappeared, and the melting width decreased from 1.10 mm to 0.98 mm. Adjusting the key welding parameters can realize the disappearance of the crystallization phenomenon in the weld zone and reduce the degree of crystallization in the heat-affected zone. Larger laser power and higher welding speed are more conducive to obtaining the welded joints with small melting width and low crystallinity. The hardness of the weld zone is similar to that of the base material while the heat-affected zone has the highest hardness due to crystallization.