铜基金属粉末选区激光烧结的工艺研究

优化工艺参数（激光功率275～1125W，扫描速率0．04～0．06m／s，扫描间距0．15～0．30mm），对多组份铜基金属粉末（组份包括纯Cu，预合金CuSn和预合金CuP）进行了选区激光烧结（SLS）实验，其成形机制为粉末部分熔化状态下的液相烧结机制。在保证适宜的成形机制的前提下，研究了激光功率、扫描速率、扫描间距、铺粉厚度等工艺参数对烧结组织及性能的影响。结果表明，适当增加激光功率或减小扫描速率能改善烧结致密度及组织连续性。减小扫描间距致使烧结线从断续分布连续转变为较为平整的结合状态，组织致密性及均匀性显著提高。减小铺粉厚度有利于改善层问结合性；但最小铺粉厚度需适当选择，否则会因凝固收缩效应及铺粉不均匀性而降低烧结致密度。

Processing Conditions of Cu-Based Metal Powder in Selective Laser Sintering

Experimental investigations on selective laser sintering (SLS) of multi-component Cu-based metal powder, which consists of pure Cu, pre-alloyed CuSn, and pre-alloyed CuP, were performed. The laser power of 275～425 W, scan speed of 0.04～0.06 m/s, and scan line spacing of 0.15～0.30 mm were optimized. The bonding mechanism of this process is liquid phase sintering with partial melting of the powder occurred. With the workable sintering mechanism ensured, the effects of the processing parameters such as laser power, scan speed, scan line spacing, and layer thickness on the densification and attendant microstructures were studied. It was found that increasing laser power or decreasing scan speed leads to higher sintered density and structural homogeneity. A successive transition from discontinuous scan tracks to coherently bonded ones occurs with decreasing scan line spacing, leading to an improvement in densification. Lowering layer thickness promises a sound bonding between sintered layers. However, care should be taken to determine the minimum layer thickness that can be used; otherwise the densification may be damaged due to the excessive solidification shrinkage and inhomogeneous dispersion of the powder.