激光冲击MAG复合增材工艺与组织性能研究

Study on laser impact MAG hybird additive technology and analysis of microstructure and mechanical properties

为了研究激光冲击熔化极活性气体保护焊(Metal Active-Gas welding,MAG)复合增材工艺规律,通过构建复合热源模型,对比研究激光加入前后电弧及熔池的变化,并通过改变激光功率参数,分别分析其对增材成形件宏观形貌、微观组织和力学性能的影响。结果表明,在激光的冲击作用下,电弧产生吸引和压缩现象,可提高电弧的稳定性和热源利用率、增加熔池内气体逃逸时间、细化成形件晶粒尺寸,以及提高成形件的力学性能。激光功率900 W为最佳工艺参数,此时增材成形件表面较为光滑、晶粒尺寸最小范围为5~16μm,平均显微硬度为(182.5±8.7)HV,抗拉强度为566 MPa,断后伸长率为10.35%,气孔率为0.74%。对比单电弧增材成形件,平均显微硬度、抗拉强度和断后伸长率分别提高了9.3%、13.4%、37.5%,气孔率减少了43.1%。

In order to study the technological law of laser impact MAG hybird additive,by building a hybird heat source model,the changes of arc and molten pool before and after laser addition were compared,and the laser power parameters were changed to analyze its influence on the macro-morphology,microstructure and mechanical properties of additive parts.The results show that under the impact of laser,the electric arc generates attraction and compression,which can improve the stability of electric arc and the utilization rate of heat source,increase the escape time of gas in molten pool,refine the grain size of formed parts and improve the mechanical properties of formed parts.When the laser power is 900 W,it is the best process parameter.At this time,the surface of the formed part is smooth,the minimum grain size is 5~16μm,the average microhardness is(182.5±8.7)HV,the tensile strength is 566 MPa,the elongation after fracture is 10.35%,and the porosity is 0.74%,which are increased by 9.3%,13.4%,and 0.74% respectively compared with the single arc additive formed part.The porosity is reduced by 43.1%.