激光熔覆工艺对镁合金显微组织的影响研究

ABSTRACTABSTRACTIn order to investigate the influence of laser cladding technology on themicrostructure of AZ31 alloy,this article will use Al powder laser cladding on thesurface of magnesium alloy to detect the microstructure and properties of the claddinglayer.This article selects three different process parameters,namely laser power,powder feeding speed,and scanning speed,to explore the impact on laser cladding.Atotal of 9 sets of experimental parameters were set up for orthogonal experimentsbased on these three factors.High purity Al powder was melted onto AZ31 alloyusing laser cladding technology to prepare an Al Mg composite coating.GX71Fmetallographic microscope and HVS-1000Z microhardness tester were used toobserve the microstructure of the substrate,Heat-affected zone and cladding layer.The hardness of base material and Heat-affected zone was measured,and thefollowing research results were obtained:After experiments,it was found that laser power and scanning speed are the mainfactors affecting laser cladding,which have a significant impact on the experiment.Atthe same time,the optimal process parameters were also found in this experiment.When the laser power is 1250w,the powder feeding speed is 3.6g/min,and thescanning speed is 44.4mm/s,the cladding layer obtained is continuous,uniform,anddefect free.The metallographic microscope observation of the sample shows that theinterface zone,Heat-affected zone and cladding layer are respectively from the basematerial to the cladding layer.There are columnar crystals at the junction,anddendritic zones in the Heat-affected zone.Keywords:laser cladding laser power scanning speed powder feeding speedHeat-affected zone