Processing Optimization On Surface Quality Of Selective Laser Melted CuZrCr Alloy

CuZrCr copper alloy possess excellent properties,such as high strength,high electrical and thermal conductivity.Therefore,it has been widely used in the fields of aerospace,electronic power,transportation and new energy.With the development of industry,traditional processing methods of CuZrCr alloy are difficult to meet the requirements of emerging industries and national major projects.Selective Laser Melting(SLM),as a most promising additive manufacturing technology,has attracted increasing attention.It provides the possibility of manufacturing advanced CuZrCr alloy products due to its permission of high degree of design freedom,high material utilization,ability of fabricating parts with complex structures,etc.In this paper,the surface processing parameter optimization of SLM technology was performed to manufacture CuZrCr coper alloy with a higher surface quality.Experimental methods were used to analysis the effects of processing parameters on the surface roughness and the corresponding results were concluded.The main results are as follows:(1)The mechanism of SLM forming part surface is analyzed,including the interaction mechanism of laser and powder,the surface-forming environment,the main defects of forming surface.Based on the absorption rate of the powders,the interaction between laser and powder is analyzed.According to the forming characteristics,the part surfaces are divided into top surface,side surface and overhanging surface.The effects of balling agglomeration and staircase effect on the forming surface quality were analyzed.(2)The influence of processing parameters on the forming quality of the top surface is studied.A relatively optimal top surface is obtained under high laser power and low scanning speed.The main defect on the top surface is balling phenomenon.From the results of experiment,it is found that low laser power and high scanning speed will cause balling phenomenon witch worsen the surface quality and there are interactive effects between different process parameters.(3)The upper surface,the down surface,and the vertical surface have low surface roughness under high laser power and low scanning speed.The main defects on the side surface are agglomeration and balling phenomenon.Increasing laser power can significantly reduce balling and agglomeration phenomena,while increasing scanning speed worsen these phenomena.(4)The influence of the processing parameters and the number of scanning overhanging layers on the forming quality of the overhanging surface are studied.A relatively optimal overhanging surface was obtained under high laser power and high scanning speed.The strong agglomeration phenomenon is the main defect on the overhanging surface.This agglomeration phenomena are different at different scanning speed and hatch space under high or low laser power condition.Besides,it was found that the number scanning overhanging layers has a significant effect on the thickness of agglomeration on the overhanging surface.