球形石墨粉末选择性激光烧结成形工艺研究  

Selective Laser Sintering Forming Process of Spherical Graphite Powder

作　　者：吴海华 戢运鑫[1] 吴正佳 郝佳欢 魏恒[1] 龚亮 张华龙 高澳冬 WU Haihua;JI Yunxin;WU Zhengjia;HAO Jiahuan;WEI Heng;GONG Liang;ZHANG Hualong;GAO Aodong(College of Mechanical and Power Engineering,China Three Gorges University,Yichang 443002;Hubei Engineering Center of Graphite Additive Manufacturing Technology and Equipment,China Three Gorges Univer-sity,Yichang 443002)

机构地区：[1]三峡大学机械与动力学院,宜昌443002 [2]三峡大学石墨增材制造技术与装备湖北省工程研究中心,宜昌443002

出　　处：《特种铸造及有色合金》2024年第6期728-735,共8页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51575313)。

摘　　要：研究了不同的球形石墨粉末与人造石墨体积比、包覆预处理次数以及激光能量密度对选择性激光烧结(SLS)石墨件成形精度和抗弯强度的影响,揭示了其内在机理,并通过正交试验进一步确定最优工艺参数组合,获得细小特征尺寸的多孔石墨骨架。结果显示,在石墨粉末与黏结剂组成确定的前提下,提高人造石墨粉末与球形石墨体积比有助于提升混合粉末堆积密度、导热系数以及SLS石墨件抗弯强度,但对其成形精度不利。通过对石墨粉末进行包覆预处理,提高了粉末间有效黏结力,在降低混合粉末导热系数、提高堆积密度的同时保证了SLS石墨件抗弯强度和成形精度,最终选择合理的工艺参数组合成功打印出结构完整、最小特征尺寸为?1.0 mm的类金刚石多孔石墨骨架,其素坯X、Y轴方向尺寸相对误差控制在2%以内,Z轴方向尺寸相对误差为8.25%,抗弯强度达到2.84 MPa。Effects of different volume ratios of spherical graphite powder to artificial graphite,cladding pretreatment times,and laser energy density on molding accuracy and bending strength of SLS graphite components were investi⁃gated,and the mechanisms were revealed.The optimal combination of process parameters was further determined by orthogonal experiments to obtain porous graphite skeletons with fine feature sizes.The results indicate that under the certain composition,by increasing the volume ratio of artificial graphite powder to spherical graphite,it contributes to the stacking density and thermal conductivity of the mixed powder as well as the bending strength of SLS graphite com⁃ponents,which is adverse to molding accuracy.After the graphite powder cladding pretreatment,the effective bonding force between the powders is increased,ensuring the bending strength and molding accuracy of SLS graphite parts under the premise of reducing thermal conductivity and enhancing the stacking density.Finally,a reasonable combina⁃tion of process parameters was selected to successfully print out a diamond-like porous graphite skeleton with a com⁃plete structure and a minimum feature size ofϕ1.0 mm,where the relative error of billet size along the X⁃and Y⁃axis is controlled below 2%,and that along the Z-axis is 8.25%,and bending strength reaches 2.84 MPa.

关 键 词：球形石墨粉末 选择性激光烧结 成形精度 抗弯强度 

分 类 号：TG113.25[金属学及工艺—物理冶金]