激光选区熔化纯钨防散射栅格的工艺及性能研究  

Selective Laser Melting Process and Performance of Pure Tungsten Anti-Scatter Grid

作　　者：王迪[1] 胡伟南 杨永强[1] 冯永伟 张英杰[2] 伊浩 Wang Di;Hu Weinan;Yang Yongqiang;Feng yonwei;Zhang Yingjie;Yi Hao(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510641,China;Xianming Wu School of Intelligent Engineering,South China University of Technology,Guangzhou 511442,China;School of Mechanical and Vehicle Engineering,Chongqing University,Chongqing 400030,China)

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510641 [2]华南理工大学吴贤铭智能工程学院,广东广州511442 [3]重庆大学机械与运载工程学院,重庆400030

出　　处：《稀有金属》2023年第5期757-768,共12页Chinese Journal of Rare Metals

基　　金：广东省基础与应用基础研究基金项目(2019B1515120094)资助。

摘　　要：为探究激光选区熔化(SLM)成形纯钨防散射栅格的最佳工艺参数,研究了不同工艺参数对于栅格试样的表面粗糙度、熔道厚度、压缩力学性能以及钨实体试样致密度、微观组织的影响规律。研究发现,栅格试样的表面粗糙度会随着激光功率和扫描速度的增加而增加,过高的激光功率容易产生球化现象。此外,激光功率的增加以及扫描速度的减小都会使得熔道的厚度尺寸增加,在200 W激光功率以及500 mm·s^(-1)扫描速度工艺条件下熔道厚度最为接近100μm的预设值。压缩测试结果表明,纯钨薄壁栅格件的抗压强度会随着激光功率的增加以及扫描速度的减小而增加,且试样最大抗压强度达到了172 MPa。实体试样的致密度会随着激光扫描速度增加而减小,并且随着激光功率的增加先增大再减小,最终在375 W激光功率以及500 mm·s^(-1)扫描速度工艺条件下获得98.36%的最大致密度。其构建方向组织多为柱状晶粒,并且晶粒会随着激光功率的减小以及扫描速度的增加而细化。最后根据探究的工艺参数对栅格熔道形貌及厚度尺寸的影响规律,通过工艺优化,在210 W-600 mm·s^(-1)以及375 W-500 mm·s^(-1)条件下分别成形了防散射栅格的栅格和实体部分,成功打印的栅格熔道形貌较好、且具有较高的成形精度((100±10)μm)。Due to its high density and excellent radiation absorption,tungsten and its alloys are often used to prepare anti-scatter grids for absorbing scattered X-rays in computed tomography(CT)scans to improve imaging quality.Compared with traditional manu-facturing,the pure tungsten anti-scatter grid prepared by selective laser melting(SLM)technology has the characteristics of high forming rigidity,thin wall thickness,high density,strong ability to absorb scattered radiation,and good shading degree and the research of SLM forming thin-walled tungsten parts gradually rises.At present,the research on SLM-formed tungsten thin-walled grid mainly fo-cused on the thickness of the melt channel and its surface roughness,and had not explored its mechanical properties,the overall form-ability and forming accuracy of the anti-scatter grid.In order to explore the optimal process parameters and performance of SLM form-ing pure tungsten anti-scatter grid.In this paper,spherical pure tungsten powder was used to print tungsten solid and grid samples un-der different laser power and scanning speed conditions.The density of the solid sample was measured by the Archimedes drainage method,and the internal defects and microstructure of the melt channel were observed by optical microscope(OM).Finally,the mi-crohardness was measured under the condition of 1.96 N loading and 10 s loading time.The grid sample was used to observe the mor-phology of the melt channel and measure the thickness of the melt channel using a three-dimensional microscope with a super depth of field.The study found:(1)The increase of laser power and scanning speed would improve the powder stickiness of the melt channel,but increase the surface roughness of the melt channel.The spheroidization caused by the laser power above 225 W would seriously af-fect the surface roughness of the melt channel.(2)When the wall thickness of the melt channel was not less than the powder particle size,the limit width of the melt channel was mainly determined by the laser spot.Due to the hi

关 键 词：激光选区熔化(SLM) 纯钨 薄壁 力学性能 致密度 

分 类 号：TF803.21[冶金工程—有色金属冶金]