( 1. 南京航空航天大学 材料科学与技术学院， 南京 210016；
2. 中国工程物理研究院 机械制造工艺研究所， 绵阳 621900)
摘 要: 研究了选区激光烧结专用多组分铜基金属粉末（组分包括纯Cu， 预合金CuSn， CuP）的烧结性能。结果表明， 通过合理控制激光工艺参数（特别是激光功率和扫描速率）， 能顺利实现粉末烧结成形， 且无明显的“球化”效应和翘曲变形。 扫描电镜和X射线衍射分析证实， 此组粉末体系的激光烧结是基于液相烧结机制， 其中熔点较低的CuSn充当粘结金属，熔点较高的Cu充当结构金属； 而添加元素P则起稀释剂的作用， 能避免Cu颗粒表面氧化。 研究了粉末体系中粘结金属含量对粉末烧结致密化和烧结件微观组织的影响。 结果表明， 在一定范围内粘结金属含量的提高有利于改善烧结致密度；但若粘结金属过量， 则会因“球化”效应而降低致密度。
关键字: 快速原型制造；选区激光烧结； 铜基金属粉末； 液相烧结； 添加剂
（ 1. College of Materials Science and Technology,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
2. Institute of Machinery Manufacturing Technology,
China Academy of Engineering Physics, Mianyang 621900, China）
Abstract: Selective laser sintering of a special multi-component Cu-based metal powder which consists of high-purity Cu, pre-alloyed CuSn and CuP was processed. The experimental results show that choosing suitable laser processing parameters, especially laser power and scanning rate, can effectively control “balling” effect and curling deformation during laser sintering. The scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses show that the bonding mechanism of this process is liquid phase sintering, during which the Cu powder with higher melting point acts as the structure metal; while the CuSn powder with lower melting point acts as the binder. The element phosphorus acts as fluxing agent to react with oxygen, preventing the Cu particles form oxidation. The influence of the content of binder in powder system on the densification and attendant microstructural features of the sintered samples was investigated. It is found that with the increase of the binder content, the microstructures become denser; however, an excess of binder results in “balling” phenomena, hence damaging the densification.
Key words: rapid prototyping; selective laser sintering; Cu-based metal powder; liquid-phase sintering; additive
