多组分铜基金属粉末选区激光烧结试验研究

 对自行设计制备的多组分铜基金属粉末(组分包括纯Cu粉末、预合金CuSn和CuP粉末)进行了激光烧结实验。工艺研究结果表明,该粉末体系在一定的激光参数和铺粉参数条件下,可实现对"球化"效应和翘曲变形的有效控制。利用X射线衍射仪和扫描电镜研究了激光烧结试样的物相、表面形貌和显微组织。结果表明,多组分铜基金属粉末的成形机制为液相烧结机制,粘结金属CuSn熔化形成的液相渗入结构金属Cu颗粒之间,通过液相的"桥接"作用而形成烧结颈,从而充分粘结未熔Cu颗粒;而P元素则起稀释剂的作用,在烧结过程中与氧反应生成CuPO₃,使金属颗粒表面避免氧化。最后给出了激光烧结上述金属粉末制造齿轮的加工实例,其致密度达理论密度的82％,而横向尺寸误差仅为1.9％。

Experimental Research on Selective Laser Sintering of Multi-component Copper-based Metal Powder

Selective laser sintering (SLS) of a self-developed multi-component Cu-based metal powder is investigated. The powder system consists of a mixture of pure Cu powder, pre-alloyed CuSn and CuP powder. The experimental results demonstrate that choosing suitable laser processing parameters and layer thickness can effectively control "balling" effect and curling deformation in laser sintering of this powder system. The X-ray diffraction (XRD) and scanning electron microscope (SEM) are used to analyze the structural phase, surface morphology and microstructure of the laser-sintered sample. It shows that the bonding mechanism of this multi-component Cu-based metal powder is liquid-phase sintering. The binder CuSn melts and infiltrates into the pores between the Cu particles and solidifies to form sintering necks, which sufficiently bond the structural metal Cu. The element phosphorus acts as flux and reacts with oxygen to form CuPO₃ in SLS process, which prevents the Cu particles form oxidation. A case study on SLS of this Cu-based metal powder to fabricate a gear is carried out. 82% relative theoretical density and transverse dimension error of 1.9% are achieved.