选区激光熔化316L不锈钢多孔过滤零件的组织性能研究

【目的】揭示选区激光熔化316L不锈钢粉末成型多孔过滤零件的成型规律和机理。【方法】试验设计孔洞尺寸为1 mm的圆形、正方形多孔316L不锈钢过滤零件,采用选区激光熔化方法进行成型,选用光学显微镜、扫描电子显微镜、X射线衍射等手段对其组织特征和性能进行分析检测,采用显微硬度计测量其显微硬度。【结果】获得了无气孔、裂纹、偏析等缺陷,且致密度达到95%的成型组织。组织内部主要由垂直于界面呈现外延生长的树枝晶组成,所得组织分层均匀,各层间呈冶金结合,定向凝固特征明显。【结论】多孔过滤零件成型件由奥氏体组成,显微硬度为:258~294 HV0.3。采用选区激光熔化方法可以成型孔洞尺寸较小的过滤零件。

Microstructures and properties of porous filter parts of selective laser melted 316L stainless steel

Objective]To reveal the formation patterns and mechanisms of selective laser melted 316 L stainless steel porous filter parts. Method]Both cubical and cylindrical 316L stainless steel porous filter parts with 1 mm pore size were designed and formed by selective laser melting ( SLM) . Microstructures and properties of these filter parts were investigated using optical microscope, scanning electron micro-scope and X-ray diffraction. Micro hardness of the parts was measured using microhardness tester.Re-sult]The formed filter parts were obtained with 95% density and without defects such as pore, crack and segregation . The intra-structure was mainly composed of dendrite crystals which were vertical to the inter-face and grew along the epitaxy. The microstructure obtained had even layers which were metallurgically bonded. There was clear evidence of directional solidification for the formed parts. Conclusion] The formed parts are composed of austenite, and microhardness ranges from 258 to 294 HV0. 3. SLM can be used in prototyping filter parts with relatively small pore size.