Influence of Surface Mechanical Attrition Treatment (SMAT) on Microstructure, Tensile and Low-Cycle Fatigue Behavior of Additively Manufactured Stainless Steel 316L
Influence of Surface Mechanical Attrition Treatment (SMAT) on Microstructure, Tensile and Low-Cycle Fatigue Behavior of Additively Manufactured Stainless Steel 316L
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DOI：
10.3390/met12091425
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发表时间：
2022-08
期刊：
影响因子：
2.9
通讯作者：
T. Wegener;Tao Wu;F. Sun;Chong Wang;Jian Lu;T. Niendorf
中科院分区：
文献类型：
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作者：
T. Wegener;Tao Wu;F. Sun;Chong Wang;Jian Lu;T. Niendorf
直接能量沉积（DED）作为一种常见的增材制造技术，能够制造出具有复杂几何形状的接近净成形的金属零件。表面机械研磨处理（SMAT）是一种先进的表面处理技术，它能够产生以压缩残余应力和加工硬化为特征的纳米结构表面层，从而改善金属试件的疲劳性能。在本研究中，不锈钢316L试样制造的DED和随后的表面处理SMAT。单轴拉伸试验和单轴拉压低周疲劳试验进行了竣工和SMAT处理的标本。通过粗糙度和硬度测量、扫描电子显微镜和透射电子显微镜对两种条件下的显微组织进行了表征。SMAT后，在表面层中发现了纳米晶和微孪晶。这些微观结构特征有助于处理表面的上级性能。最后，可以得出结论，SMAT工艺可以改善增材制造钢在静态和疲劳载荷下的机械性能。
Direct Energy Deposition (DED), as one common type of additive manufacturing, is capable of fabricating metallic components close to net-shape with complex geometry. Surface mechanical attrition treatment (SMAT) is an advanced surface treatment technology which is able to yield a nanostructured surface layer characterized by compressive residual stresses and work hardening, thereby improving the fatigue performances of metallic specimens. In the present study, stainless steel 316L specimens were fabricated by DED and subsequently surface treated by SMAT. Both uniaxial tensile tests and uniaxial tension-compression low-cycle fatigue tests were conducted for as-built and SMAT processed specimens. The microstructure of both conditions was characterized by roughness and hardness measurements, scanning electron microscopy and transmission electron microscopy. After SMAT, nanocrystallites and microtwins were found in the top surface layer. These microstructural features contribute to superior properties of the treated surfaces. Finally, it can be concluded that the mechanical performance of additively manufactured steel under static and fatigue loading can be improved by the SMAT process.