Microstructure Evolution, Phase Formation, Corrosion, and Mechanical Properties of Stainless Steel Fabricated by Extrusion-Based Sintering-Assisted Additive Manufacturing
Microstructure Evolution, Phase Formation, Corrosion, and Mechanical Properties of Stainless Steel Fabricated by Extrusion-Based Sintering-Assisted Additive Manufacturing
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DOI：
10.1016/j.addma.2023.103746
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发表时间：
2023-08
影响因子：
11
通讯作者：
Fu-ji Wang;S. You;Dayue Jiang;Xiangyu Yuan;R. Fu;F. Ning
中科院分区：
文献类型：
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作者：
Fu-ji Wang;S. You;Dayue Jiang;Xiangyu Yuan;R. Fu;F. Ning
在金属添加剂制造(AM)领域，熔融纤维制造(FFF)、脱粘和烧结工艺采用高填充金属颗粒的聚合物基纤维被认为是制造大尺寸和耐火致密金属部件的经济解决方案。烧结作为一个关键步骤，对最终零件的显微组织均匀性起着至关重要的作用。在烧结过程中，金属件中元素和相的分布和含量决定了所获得的材料性能。本工作对316L不锈钢FFF印制件在整个烧结过程中的组织演变进行了表征和了解。通过对316L不锈钢在不同烧结温度下的晶粒形貌的分析，发现了包括层间气孔和位错密度在内的独特的层间微结构。通过相平衡模拟、物相表征和元素分析，建立了铬元素在晶界偏聚与δ-铁素体相形成的关系。最后对烧结温度曲线进行了优化，实现了直接制备抗点蚀性能和力学性能优良的单相奥氏体不锈钢。这项工作的发现将对FFF奥氏体不锈钢的介观烧结行为提供很好的见解，为定制元素/相分布以控制AM制造的金属合金的组织铺平新的途径
In the domain of metal additive manufacturing (AM), a Fused Filament Fabrication (FFF), Debinding, and Sintering process that adopts polymer-based filaments with highly filled metal particles can be considered an economical solution to create large-size and refractory dense metal parts. Sintering, as a critical step, plays a critical role in determining the resultant microstructure uniformity of final parts. During sintering, the distribution and content of elements and phases in metal parts dictate the achieved material properties. In this work, the microstructure evolution during the entire sintering of FFF-printed 316L stainless steel (SS) parts was characterized and understood. The unique interlayer microstructures including interlayer pores and dislocation density were uncovered by characterizing grain morphologies of 316L SS at different sintering temperatures. Subsequently, the relationship between the chromium element segregation at the grain boundary and the formation ofδ-ferrite phases was established through phase equilibrium simulation, phase characterization, and element analysis. Finally, the sintering temperature curve was optimized to achieve the direct preparation of single-phase austenitic SS with excellent pitting corrosion resistance and mechanical properties. The findings of this work will provide great insights into the mesoscale sintering behavior of FFF-built austenitic SS, paving new avenues for tailoring element/phase distribution to control the microstructure of metal alloys built by AM.