选区激光熔化制备金刚石/铝复合材料的缺陷研究

Study on defects of diamond/aluminum composites prepared by selective laser melting

利用选区激光熔化(selective loser melting,SLM)技术成功制备金刚石增强铝基复合材料。通过对成型之后的断口、金刚石颗粒以及成型过程中飞溅残渣的分析,发现复合材料的主要缺陷为金刚石在激光照射条件下的热损伤以及在成型过程中形成的大量孔洞。分析表明:金刚石的热损伤主要是由激光直接作用在金刚石上导致的石墨化,金刚石表层的TiC镀层也无法避免其损伤;金刚石间的内部孔洞主要是因为在极短的熔化成型过程中金刚石和基体润湿性较差,相互难以融合而形成的大量孔洞。

Diamond reinforced aluminum matrix composites have been successfully fabricated by selective laser melting(selective laser melting,SLM).The fracture and the diamond particles were observed and analyzed in the forming process.The main defects of the composite are the thermal damage of diamond and a large number of holes.The analysis shows that the thermal damage of diamond is mainly caused by the graphitization of diamond which is generated by the direct irradiation of laser.The TiC coating on the surface of diamond could not protect diamond from laser damage.The holes among diamond particles are mainly due to the poor wettability between diamond and matrix during SLM process in an extremely short period,which can not melt easily.So that,a large number of holes are formed.