High Strength and Ductility of Additively Manufactured 316L Stainless Steel Explained
High Strength and Ductility of Additively Manufactured 316L Stainless Steel Explained
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DOI：
10.1007/s11661-018-4607-2
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发表时间：
2018-07-01
影响因子：
2.8
通讯作者：
Newman, Tabitha A.
中科院分区：
文献类型：
--
作者：
Shamsujjoha, Md.;Agnew, Sean R.;Newman, Tabitha A.
探索了增材制造的316L不锈钢的结构-性能关系。扫描电子显微镜和电子背散射衍射（EBSD）分析显示，一个精细的细胞枝晶（0.5至2 μ m）的子结构内大的不规则形状的晶粒（类似于100 μ m）。胞状结构沿沿着aOE（c）100 >晶体学方向生长。然而，织构分析表明，主要的aOE（c）100 >织构分量从建筑方向倾斜了大约15度。X射线衍射线轮廓分析表明，在竣工材料中具有类似于1 x 10（15）m（-2）的高位错密度，这与通过传统的泰勒硬化方程观察到的EBSD微观结构和高屈服强度很好地相关。观察到水平（HB）和垂直（VB）构建样品的应变硬化行为和延展性的显着变化。HB和VB样品的延展性分别为49%和77%。拉伸变形过程中的初始生长织构和随后的织构演变负责所观察到的各向异性。值得注意的是，变形样品的EBSD分析显示出变形孪晶，其主要形成在晶粒中，aOE（c）111 >平行于加载方向排列。VB样品表现出更高的孪生活性，在高应变下更高的应变硬化速率，因此，更高的延展性。退火样品的分析表明，所观察到的微观结构和性能是热稳定的，只有适度的强度下降和非常相似的水平的延展性和各向异性，与建成条件相比。
Structure-property relationships of an additively manufactured 316L stainless steel were explored. A scanning electron microscope and electron backscattered diffraction (EBSD) analysis revealed a fine cellular-dendritic (0.5 to 2 mu m) substructure inside large irregularly shaped grains (similar to 100 mu m). The cellular structure grows along the aOE (c) 100 > crystallographic directions. However, texture analysis revealed that the main aOE (c) 100 > texture component is inclined by similar to 15 deg from the building direction. X-ray diffraction line profile analysis indicated a high dislocation density of similar to 1 x 10(15) m(-2) in the as-built material, which correlates well with the observed EBSD microstructure and high-yield strength, via the traditional Taylor hardening equation. Significant variations in strain hardening behavior and ductility were observed for the horizontal (HB) and vertical (VB) built samples. Ductility of HB and VB samples measured 49 and 77 pct, respectively. The initial growth texture and subsequent texture evolution during tensile deformation are held responsible for the observed anisotropy. Notably, EBSD analysis of deformed samples showed deformation twins, which predominately form in the grains with aOE (c) 111 > aligned parallel to the loading direction. The VB samples showed higher twinning activity, higher strain hardening rates at high strain, and therefore, higher ductility. Analysis of annealed samples revealed that the observed microstructures and properties are thermally stable, with only a moderate decrease in strength and very similar levels of ductility and anisotropy, compared with the as-built condition.