选区激光熔化制备原位TiN-Ti5Si3复合材料的显微组织

MICROSTRUCTURES OF IN SITU TiN-Ti_5Si_3 COMPOSITES PREPARED BY SELECTIVE LASER MELTING

利用高能球磨制备了Si_3N_4-Ti(摩尔比1:9)纳米复合粉末,Si_3N_4和Ti平均晶粒尺寸均小于20 nm,之后进行选区激光熔化成型,通过9Ti+Si_3N_4=4TiN+Ti_5Si_3反应生成TiN增强Ti_5Si_3基原位复合材料.延长球磨时间,Si_3N_4-Ti复合粉末颗粒细化且比表面积增加,激光成型的TiN-Ti_5Si_3复合材料致密度可增至97.2%,成型组织中TiN增强相形貌经历多棱角状→近圆形→枝晶状的转变.

The selective laser melting（SLM） was used to process the high-energy ball milled Si3N4-Ti（mole ratio of 1：9） nanocomposite powder in which the average grain sizes of Si3N4 and Ti were both less than 20 nm.The TiN reinforced Ti5Si3 matrix in situ composites were prepared by means of the synthesis reaction 9Ti＋Si3N4=4TiN＋Ti5Si3.As the milling time increased,the average particle size of the milled Si3N4-Ti composite powder decreased and the resultant specific surface area increased.The densification level of laser processed TiN-Ti5Si3 composites increased accordingly to 97.2%.The morphologies of TiN reinforcing phase in the corresponding SLM processed structures experienced a successive change from a poly-angular shape to a near-spherical shape and finally to a dendritic shape.