X-ray computed tomography analysis of pore deformation in IN718 made with directed energy deposition via in-situ tensile testing
X-ray computed tomography analysis of pore deformation in IN718 made with directed energy deposition via in-situ tensile testing
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DOI：
10.1016/j.ijsolstr.2022.111943
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发表时间：
2022-08
影响因子：
3.6
通讯作者：
O. L. Kafka;Cheng Yu;Puikei Cheng;S. Wolff;Jennifer L. Bennett;E. Garboczi;Jian Cao;Xianghui Xiao;Wing Kam Liu
中科院分区：
文献类型：
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作者：
O. L. Kafka;Cheng Yu;Puikei Cheng;S. Wolff;Jennifer L. Bennett;E. Garboczi;Jian Cao;Xianghui Xiao;Wing Kam Liu
定向能量沉积 (DED) 是一种金属增材制造技术，通常用于大型部件和零件修复。它可能导致材料性能不同于传统加工金属。这项工作使用原位射线计算机断层扫描来研究镍基合金 IN718 拉伸性能的空间和方向差异，以观察内部孔隙群。在测量变形过程中孔隙形状的演变时，显示了机械性能的各向异性和空间变异性。将测量的孔隙变形与使用计算晶体塑性方案模拟的预测变形进行比较，该方案通过逆向建模提供对孔隙所在晶粒取向的洞察。这些测量提供了一种高保真度方法来比较孔隙变形研究的实验方法和计算方法。孔隙变形测量表明，孔隙倾向于沿载荷方向生长和伸长，这与延性变形一致，并且可能随材料变形。一般来说，在这种材料中观察到的孔隙缺陷（不是由于缺乏熔合）不会导致所谓的过早失效，并且在断裂之前会发生充分发展的颈缩。
Directed energy deposition (DED) is a metal additive manufacturing technique often used for larger-scale components and part repair. It can result in material performance that differs from conventionally processed metal. This work studies spatial and orientation-based differences in tensile properties of nickel-based alloy IN718 usingin-situx-ray computed tomography to observe internal pore populations. Anisotropy and spatial variability in mechanical properties are shown while the evolution of pore shape during deformation is measured. Measured pore deformation is compared to predict deformations simulated using a computational crystal plasticity scheme, which provides insight, through inverse modeling, to the grain orientation in which the pore resides. The measurements provide a high fidelity method to compare experimental and computational approaches to pore deformation studies. Pore deformation measurements show that pores tend to grow and elongate in the direction of loading, consistent with ductile deformation and likely deforming with the material. Generally, the pore defects observed in this material (not from lack-of-fusion) do not cause so-called premature failure, and fully developed necking occurs prior to fracture.