扫描路径对选择性激光熔化成形质量的影响
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摘要
基于选择性激光熔化技术,研究了不同扫描路径对Ti6Al4V成形试样的表面粗糙度、残余应力、翘曲变形的影响。结果表明:无论是长边扫描还是短边扫描,上表面的粗糙度值要明显小于侧表面的粗糙度值,和扫描方向相平行的侧表面的粗糙度值要小于和扫描方向相垂直的侧表面的粗糙度值。采取短边扫描的成形件和基板之间的残余应力值更小,且成形件和基板的最大翘曲变形相较于长边扫描减小了约35%。在SLM成形前,采取对基板进行适当预热的方式可以减小成形过程中成形件和基板之间的温度梯度,从而达到减小残余应力的目的。采取短边扫描且基板预热温度为300℃的成形件达到了99.4%的近全致密,采取短边扫描的成形件的致密度要高于采取长边扫描的成形件的致密度。实验结果表明,采取短边扫描的SLM成形件的成形质量更好。
Based on selective laser melting technology,the effects of different scanning paths on the surface roughness,residual stress and warpage of Ti6Al4V formed specimens were studied.The results show that the roughness of the upper surface is obviously less than the roughness of the side surface,and the roughness of the side surface parallel to the scanning direction is less than the roughness of the side surface perpendicular to the scanning direction,whether it is long side scanning or short side scanning.The residual stress between the forming parts and the substrate with short side scanning is less,and the maximum warping deformation of the forming parts and the substrate is reduced by about 35% compared with the long side scanning.Before SLM forming,the temperature gradient between the forming parts and the substrate can be reduced by proper preheating of the substrate,thus reducing the residual stress. The forming parts with short side scanning and the preheating temperature of 300 centigrade are nearly 99. 4%,and the compact degree of the forming parts with short side scanning is higher than that of the forming parts with long side scanning.The experimental results show that the forming quality of SLM forming parts with short side scanning is better.
Based on selective laser melting technology,the effects of different scanning paths on the surface roughness,residual stress and warpage of Ti6Al4V formed specimens were studied.The results show that the roughness of the upper surface is obviously less than the roughness of the side surface,and the roughness of the side surface parallel to the scanning direction is less than the roughness of the side surface perpendicular to the scanning direction,whether it is long side scanning or short side scanning.The residual stress between the forming parts and the substrate with short side scanning is less,and the maximum warping deformation of the forming parts and the substrate is reduced by about 35% compared with the long side scanning.Before SLM forming,the temperature gradient between the forming parts and the substrate can be reduced by proper preheating of the substrate,thus reducing the residual stress. The forming parts with short side scanning and the preheating temperature of 300 centigrade are nearly 99. 4%,and the compact degree of the forming parts with short side scanning is higher than that of the forming parts with long side scanning.The experimental results show that the forming quality of SLM forming parts with short side scanning is better.
引文
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[13]史玉升,李瑞迪,章文献,等.不锈钢粉末的选择性激光熔化快速成形工艺研究[J].电加工与模具,2010,增刊:67-72.
[2]KRUTH J P,MERCELIS P,VAN VAERENBERGH J,et al.Binding mechanisms in selective laser sintering and selective laser melting[J].Rapid Prototyping Journal,2005,11(1):26-36.
[3]杨永强,陈杰,宋长辉,等.金属零件激光选区熔化技术的现状及进展[J].激光与光电子学进展,2018,55(1):9-21.
[4]李俊峰,魏正英,卢秉恒.钛及钛合金激光选区熔化技术的研究进展[J].激光与光电子学进展,2018,55(1):29-46.
[5]杨佳,郭洪钢,谭建波.选择性激光熔化技术研究现状及发展趋势[J].河北工业科技,2017,34(4):300-305.
[6]VRANCKEN B,THIJS L.Heat treatment of Ti6Al4V produced by Selective laser melting:Microstructure and mechanical properties[J].Journal of Alloys and Compounds,2012,541:177-185.
[7]LIA Y,GU D.Thermal behavior during selective laser melting of commercially pure titanium powder:Numerical simulation and experimental study[J].Additive Manufacturing,2014,1-4:99-109.
[8]CHALKER P R,CLARE A,DAVIES S,et al.Selective laser melting of high aspect ratio 3D nickel-titanium structures for MEMS applications[J].Materials Research Society.2006,890(1):93-98.
[9]TANG Y,LOHA H T,WONG Y S,et al.Direct laser sintering of a copper-based alloy for creating three-dimensional metal parts[J].Journal of Materials Processing Technology,2003,140:368-372.
[10]王燕.选区激光烧结制备多孔Ni基合金的显微组织及其冶金机理[D].南京:南京航空航天大学,2011.
[11]孙鸿卿,钟敏霖,刘文今,等.定向凝固镍基高温合金上激光熔覆Inconel 738的裂纹敏感性研究[J].航空材料学报,2005,25(2):26-31.
[12]熊征,曾晓燕.在GH4133锻造高温合金叶片上激光熔覆stellite X-40合金的工艺研究[J].热加工工艺,2006,35(23):62-64.
[13]史玉升,李瑞迪,章文献,等.不锈钢粉末的选择性激光熔化快速成形工艺研究[J].电加工与模具,2010,增刊:67-72.