AM Bench 2022 Macroscale Tensile Challenge at Different Orientations (CHAL-AMB2022-04-MaTTO) and Summary of Predictions.

The additive manufacturing benchmarking challenge described in this work was aimed at the prediction of average stress-strain properties for tensile specimens that were excised from blocks of non-heat-treated IN625 manufactured by laser powder bed fusion. Two different laser scan strategies were considered: an X-only raster and an XY raster, which involved a 90° rotation in the scan direction between subsequent layers. To measure anisotropy, multiple tensile orientations with respect to the build direction were investigated (e.

Surface chemistry in Ti-6Al-4V feedstock as influenced by powder reuse in electron beam additive manufacturing.

X-ray photoelectron spectroscopy (XPS) as well as scanning and transmission electron microscopy (SEM/TEM) analysis was carried out on four Ti-6Al-4V powders used in electron beam powder-bed fusion (PBF-EB) production environments: virgin low oxygen (0.080 wt% O), reused medium oxygen (0.140 wt% O), reused high oxygen (0.

Additive Manufacturing Benchmark 2022 Subcontinuum Mesoscale Tensile Challenge (CHAL-AMB2022-04-MeTT) and Summary of Predictions.

This additive manufacturing benchmarking challenge asked the modelling community to predict the stress-strain behavior and fracture location and pathway of an individual meso-scale (gauge dimensions of approximately 200 μm thickness, 200 μm width, 1mm length) tension specimen that was excised from a wafer of nickel allow IN625 manufactured by laser powder bed fusion (L-PBF). The data used for the challenge questions and answers are provided in a public dataset (https://data.nist.

Effect of Precrack Configuration and Lack-of-Fusion on the Elastic-Plastic Fracture Toughness of Additively Manufactured Ti-6Al-4V parts.

A comparison between fatigue precracked and sharp-notched Charpy-type fracture toughness specimens is presented for characterizing the elastic-plastic fracture toughness of Ti-6Al-4V parts (produced by electron beam melting, a powder bed fusion method). The effects of processing and postprocessing conditions on crystallographic texture, grain morphology, and elastic-plastic fracture toughness of additively manufactured Ti-6Al-4V parts are currently under investigation at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. The specimens tested in this work were subjected to hot isostatic pressing (HIP) for 2 h at 900°C and 100 MPa in Argon environment (sub-β transus HIP), which is a commercial postprocessing step known to seal internal porosity in additively manufactured Ti-6Al-4V parts.

Effects of laser-energy density and build orientation on the structure-property relationships in as-built Inconel 718 manufactured by laser powder bed fusion.

This study investigates the effects of build orientation and laser-energy density on the pore structure, microstructure, and tensile properties of Inconel 718 manufactured by laser powder bed fusion. Three different build conditions were selected for comparison based on previous research (namely, the conditions that resulted in the worst and best fatigue lifetimes): 0° build orientation and 38 J/mm laser-energy density, 0° build orientation and 62 J/mm laser-energy density, and 60° build orientation and 62 J/mm laser-energy density. Differences in porosity were measured between each build condition.

Instrumented Impact Testing of Miniaturized Charpy Specimens of AM Ti-6Al-4V.

An investigation on the impact toughness properties of wrought and additively manufactured (AM) Ti-6Al-4V was conducted at National Institute for Standards and Technology (NIST) Boulder by means of instrumented impact tests on miniaturized Charpy specimens. Full transition curves for absorbed energy and lateral expansion were obtained by performing tests in the temperature range between -196°C and 700°C. The effect of various parameters was investigated for AM specimens, namely specimen orientation, hot isostatic pressing (HIPing), and notch configuration (printed or machined).

Maintenance of a bone collagen phenotype by osteoblast-like cells in 3D periodic porous titanium (Ti-6Al-4 V) structures fabricated by selective electron beam melting.

Regular 3D periodic porous Ti-6Al-4 V structures were fabricated by the selective electron beam melting method (EBM) over a range of relative densities (0.17-0.40) and pore sizes (500-1500 µm).

Compression-compression fatigue of selective electron beam melted cellular titanium (Ti-6Al-4V).

Regular 3D periodic porous Ti-6Al-4V structures intended to reduce the effects of stress shielding in load-bearing bone replacement implants (e.g., hip stems) were fabricated over a range of relative densities (0.