Abstract:

The continuous carbon fiber reinforced metal matrix composites with high specific strength and low density were prepared by additive manufacturing technology. The influences of process treatment methods and parameters, such as the surface modification of the continuous carbon fiber, the overlap rate of the path, the temperature of the print head and substrate, were studied on the tensile strength of the metal matrix composites. The results showed that well infiltration and compounding could be achieved between the molten metal matrix and the continuous carbon fiber while the surface of the carbon fiber was modified. At the same time, the tensile strength of the composite material was also improved. When the overlap rate of the printing path was increased, the volume fraction of the carbon fiber during composite material and its tensile strength were both increased. The surface tension of the molten metal was decreased, and its fluidity was better when the print head temperature, substrate temperature and printing speed were increased. This was conducive to the formation of re-fusion between the deposited layers, and could also effectively avoid the formation of pore defects at the surface cracks and the path overlap area, so that the tensile strength of the composite material could be further improved.

Key words: additive manufacturing, metal matrix composites, continuous carbon fiber, Sn-Bi alloy, three dimensional direct writing

摘要：

采用增材制造工艺方法进行具有高比强度、密度小等优良性能连续碳纤维增强金属基复合材料的直接制备。研究了连续碳纤维表面改性、路径搭接率、打印喷头温度、基板温度、打印速度等过程处理方法及工艺参数对所制备金属基复合材料抗拉强度的影响。研究结果表明，对连续碳纤维原材料实施表面改性处理，可以实现制备过程中熔融金属基体与连续碳纤维之间的良好浸润复合，以提高复合材料的抗拉强度；增大路径搭接率，可以有效提高增材制造复合材料内部纤维的体积占比，从而增大其抗拉强度；升高打印喷头温度、基板温度、打印速度，可以减小熔融金属表面张力，提高其流动性，并有利于沉积层间实现良好重熔，从而有效避免在已沉积层表面裂纹处和路径搭接区凹坑处形成气孔缺陷，进一步提升复合材料的抗拉强度。

关键词: 增材制造, 金属基复合材料, 连续碳纤维, 锡铋合金, 三维直写