Defect Evolution in Tensile Loading of 316L Processed by Laser Powder Bed Fusion
Defect Evolution in Tensile Loading of 316L Processed by Laser Powder Bed Fusion
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DOI：
10.1007/s11340-021-00815-5
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发表时间：
2022-04
影响因子：
2.4
通讯作者：
J. Miers;D. Moore;C. Saldana
中科院分区：
文献类型：
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作者：
J. Miers;D. Moore;C. Saldana
众所周知，增材制造工艺产生的孔隙率和其他缺陷会影响机械性能。然而，仍然有有限的了解，关于内部缺陷结构如何影响局部应变场的演变，因为实验研究还没有提出直接测量的内部应变场的发展中存在的defens. Excipruptedin-situtensional测试在实验室为基础的X射线计算机断层扫描机被用来调查周围的内部缺陷的应变场的演变。内部应变场的演变促进了增材制造tensile coupons.Methodssamples的宏观变形中的特定缺陷的作用的检查在316 L不锈钢激光粉末床融合。利用原位加载装置使样品在断层扫描环境中经受拉伸破坏。数字体积相关性被用来直接确定局部应变水平内的增材制造的组件在附近的孔隙度defects. Resultsof孔隙度对应变局部化和最终失败的样品进行了评估。孔隙率分布的特点，包括存在的孔隙率在表面或近表面的组件，以及孔彼此的接近度被发现会影响故障的演变。早期发生的故障被认为是与相邻的孔隙率，允许快速进展的断裂Path.ConclusionsThe直接测量应变场的演变在本研究中建立了了解内部缺陷结构特性如何影响局部应变场的演变增材制造组件的可用性。这种高保真度的特性和相关的现象学观察支持验证的数值模拟框架，描述这些材料的故障轴承。
BackgroundPorosity and other defects resultant by additive manufacturing processes are well-known to affect mechanical properties. However, there remains limited understanding regarding how the internal defect structure influences the evolution of the local strain field, as experimental investigations have not presented direct measurements of the evolving internal strain field in the presence of defects.ObjectiveInterruptedin-situtensile tests in a lab-based X-ray computed tomography machine were used to investigate the evolution of the strain field around internal defects. The evolution of the internal strain field facilitated examination of the role of specific defects in the macroscopic deformation of additively manufactured tensile coupons.MethodsSamples were produced in 316L stainless steel by laser powder bed fusion. Anin situloading device was utilized to subject the samples to tensile failure within a tomographic scanning environment. Digital volume correlation was utilized to directly determine local strain levels within the additively manufactured components in the vicinity of porosity defects.ResultsEffects of porosity on strain localization and eventual failure of the samples were evaluated. Characteristics of the porosity distribution, including presence of porosity at the surface or near-surface of components, as well as the proximity of pores to each other were found to influence the evolution of failure. Early onset of failure was found to be associated with the availability of neighboring porosity that allowed for rapid progression of the fracture path.ConclusionsThe direct measurements of strain field evolution in the present study established understanding regarding how internal defect structure characteristics influence the evolution of the local strain field for additively manufactured components. This high fidelity characterization and the associated phenomenological observations have bearing for supporting validation of numerical modeling frameworks for describing failure in these materials.