选区激光熔化打印骨架结构组织研究

Study on the Microstructure of Network Structure by SLM Process

使用SLM SOLUTIONS公司SLM125型选区激光熔化仪器进行了镍基合金3D打印样品制备,分别制得了实心制品A和具有网络骨架结构的制品B。对两种制品表面形貌及内部组织解剖分析发现,两种制品内部基体部分均为致密冶金组织,熔覆颗粒界面处未见明显孔隙或杂质。其中制品B复杂网络骨架结构的获得充分说明了该激光熔覆技术对复杂微结构的制备成型具有独特技术优势。文章还对比分析了两种制品在无热处理状态下局部裂纹生长的原因,结果表明具有骨架结构的制品B内部无裂纹,但在骨架连接角位置容易生成铸造缺陷并诱发裂纹。文章还采用有限元模拟方法进行了熔池冷却过程中骨架结构中应力分布分析。

SLM equipment(SLM125,from SLM SOLUTIONS)was used to prepare nickel alloying 3D printing samples,including an inner dense sample A and a network-structure sample B.The surface morphology and inner microstructure analysis indicates that the two samples owned dense metallurgical structure in the matrix and no obvious pores or impurities were found at the interfaces among molten particles.The achievement of the sample B with complex network structure demonstrates that the SLM technique had unique advantage to produce complex tiny structures.The reason of local crack growth was also analyzed in these two samples.The results show that there is no internal crack in product B with skeleton structure.The cracks in samples B tended to form at the corners of the network structures with casting defects.In this paper,finite element simulation method was also applied to simulate the stress distribution in the network structures in the cooling process of melting pools.