选择性激光烧结成型铜基复合材料制件及其性能表征

Characterization of copper matrix composites fabricated by selective laser sintering

将Cu粉与Sn Bi58合金粉末、松香粉末混合后进行选择性激光烧结(SLS)成型及脱脂、熔渗等后处理,用扫描电镜及能谱仪(SEM-EDS)、光学显微镜(OM)、热重分析(TGA)、差示扫描量热分析(DSC)、X射线衍射(XRD)对粉末原材料、烧结试样和熔渗处理后试样的组织形貌、热性能及物相组成进行分析和表征。研究表明,球形度较好、粒径较大的Cu粉激光烧结性能更好,与Sn Bi58颗粒形成较多的烧结颈。Cu基复合材料试样的SLS成型过程为液相烧结机制:激光烧结过程中Cu颗粒不熔化,Sn Bi58合金粉末受热熔化形成液相,润湿、包覆并黏结Cu颗粒。经熔渗处理后,试样中的Cu粉部分转变为表面包覆Sn层的Cu3Sn相,空隙处由金属Bi填充,大幅提高制件的致密性和硬度。

Cu powder was mixed with Sn Bi58 alloy powder and rosin powder,and then the mixed power was sintered by selective laser sintering（SLS） process,degreasing sintering and infiltration. The microstructure,thermal properties and the phase composition of raw materials,sintered samples and infiltrated samples were analyzed and characterized by the scanning electron microscopy and energy dispersive spectroscopy（SEM-EDS）,optical microscopy（OM）,thermo-gravimetric analysis（TGA）,differential scanning calorimetry（DSC）and X-ray diffraction（XRD）. Results show that the sintering performance of Cu powder with spherical shape is better,more sintering necks can be formed with Sn Bi58 alloy melt. A liquid sintering mechanism is proposed for the fabrication of Cu-based composite material with SLS process. During the SLS process,Sn Bi58 alloy powder is melted by heat to form liquid phase,which can wet,coat and bond the spherical Cu particles. Spherical Cu powders in the SLS sample convert to Cu3 Sn compound coated with Sn layer after infiltration,and the gaps between Cu powders are filled with pure metal Bi.