粉体特性对铜基金属粉末选区激光烧结的影响

Effects of Powder Characteristics on Selective Laser Sintering of Copper-based Metal Powder

设计制备了多组分铜基金属粉末(组分包括Cu,Cu-10Sn,Cu-8.4P),并基于液相烧结机制实现了粉体激光烧结成形。研究了粉体特性(粉末粒度、颗粒形貌、化学成分、组分比例及混粉均匀性)对烧结致密度及显微组织的影响。结果表明:粗细粉末共混并使其具有较宽粒度分布,使用球形或近球形细粉,均能提高粉末松装密度及烧结致密度;元素P能充当脱氧剂而改善润湿性,但若CuP含量多于15%质量分数,会因生成过多磷渣而降低烧结性;提高粘结金属CuSn比例能使烧结致密度得以改善,但若其含量超过30%质量分数,则会导致“球化”效应;提高混粉均匀性,有利于改善烧结致密度和组织均匀性。

A multi-component copper-based metal powder, which consists of Cu,Cu-10Sn, and Cu-8. 4P, is developed. Selective laser sintering of this powder system is processed through the mechanism of liquid phase sintering. The effects of powder characteristics such as particle shape, size distribution, chemical composition, component ratio, and dispersion homogeneity on the densification and the resultant microstructures are investiga-ted. It shows that mixing coarse and fine powder with a broad size distribution and using spherical or nearspherical fine powder can lead to an increase in the density of the loose powder and thus the densification of the laser sintered powder. The element phosphorus can act as a deoxidant to improve the wettability; however excessive addition of phosphorus （more than 15 % mass fraction of CuP） shows a negative effect on sinterability due to the formation of a large amount of phosphatic slag. With increasing the content of the binder CuSn, the sintered structure becomes denser; however, at a higher mass fraction of 30%, the ＂bailing＂ effect occurs. An improvement in the dispersion homogeneity of the powder mixture leads to a high densification with a homogenous microstructure.