NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
X-ray computed tomography analysis of pore deformation in IN718 made with directed energy deposition via in-situ tensile testing
Published
Author(s)
Orion Kafka, Cheng Yu, Puikei Cheng, Sarah Wolff, Jennifer Bennett, Edward Garboczi, Jian Cao, Xianghui Xiao, Wing Kam Liu
Abstract
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 using in-situ x-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.
Kafka, O.
, Yu, C.
, Cheng, P.
, Wolff, S.
, Bennett, J.
, Garboczi, E.
, Cao, J.
, Xiao, X.
and Liu, W.
(2022),
X-ray computed tomography analysis of pore deformation in IN718 made with directed energy deposition via in-situ tensile testing, International Journal of Solids and Structures, [online], https://doi.org/10.1016/j.ijsolstr.2022.111943, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933500
(Accessed October 14, 2025)