超声振动在激光熔覆中的作用机制及研究进展

Mechanism and Research Progress of Ultrasonic Vibration in Laser Cladding

超声波在液态金属中传播时具有独特的声学效应和空化作用,在液态金属凝固过程中施加超声振动,可以使凝固组织从粗大的柱状晶转变成均匀细小的等轴晶,成分偏析现象得到明显改善,气孔、夹杂等缺陷也能够大幅减少,在解决不同合金材料铸造、焊接、熔覆难题方面均具有很大的发展潜力和广阔的应用前景。本文介绍了超声振动处理对镍基合金、不锈钢等激光熔覆层性能的提升效果,分析了超声振动处理对激光熔覆熔池金属结晶过程的作用机制,揭示了超声振动改善激光熔覆层性能的微观机理,构建了振动处理工艺、熔覆层组织结构和性能之间的对应关系;获取科学合理的超声振动施加方式和能量精准控制方法是超声振动处理在激光熔覆领域中拓展应用急需解决的问题和重要的研究方向。

Ultrasonic has unique acoustic and cavitation effects when spreading in liquid metal.The solidification structure can be changed from coarse columnar crystals to uniform fine equiaxed crystals,the segregation phenomenon can also be significantly improved,porosity,inclusion and other defects can be greatly reduced by applying ultrasonic vibration in the solidification process of liquid metal,so it has great development potential and broad application prospects in solving the casting,welding and melting problems of different alloy materials.In this paper,the enhancement effect of ultrasonic vibration treatment on laser cladding coating properties of nickel base alloy and stainless steel is introduced,and the mechanism of ultrasonic vibration treatment on metal crystallization in laser cladding pool is revealed.Revealing the micro mechanism of ultrasonic vibration to improve the performance of laser cladding coating,establishing the relationship between vibration treatment technology,microstructure and properties of cladding coating and obtaining a scientific and reasonable ultrasonic vibration application method and accurate energy control method are urgent problems and important research directions when the ultrasonic vibration treatment application is expanded in the laser cladding field.