Talyor Impact Testing of Additively Manufactured AF9628 Steel

AF 9628 is a high-strength, low-alloy steel developed by the United States Air Force for additive manufacturing, specifically designed for powder-bed fusion. Prior research has characterized its mechanical behavior under variable strain rate conditions, revealing porosity-dependent yield anisotropy, strain rate hardening, and spall strength variations. In this study, Taylor impact tests were conducted to further benchmark AF 9628's high-strain rate yield behavior. An analytical approach was first used to estimate impact-induced deformation based on conservation laws and material strength models. Numerical simulations were then conducted to model Taylor impact tests, refining predictions by incorporating strain rate-dependent hardening and porosity effects. Finally, Taylor impact tests were performed on printed cylindrical specimens and digital image correlation (DIC) was used to compare analytical, numerical and experimental results. These results were then used to refine the Johnson Cook parameters for AF 9628. Correlation between simulated and observed impact profiles confirmed the validity of key material parameters, while deviations provided insight into unaccounted physical effects, such as varying porosity. These findings contribute to the refinement of predictive modeling for AM AF 9628 under extreme loading conditions, enhancing its applicability in munitions and aerospace structures.