Effect of printing direction and thickness on the mechanical behavior of SLM fabricated Hastelloy-X
Chandrashekhar M. Pilgar, Ana M. Fernandez, S. Lucarini, Javier Segurado
Abstract
An FFT based polycrystalline homogenization framework is used to predict the temperature-dependent response of SLM parts fabricated in Hastelloy-X, and to ascertain the origin of the differences in the mechanical response experimentally observed for different printing directions and part thicknesses. Several specimens are considered, built and loaded in different directions and having variable thicknesses. The crystal response is modeled using a crystal plasticity model. The alloy microstructure for each specimen is represented by a Representative Volume Element which reproduces the grain size, shape (aspect ratio), and orientation distributions experimentally measured. The resulting model is able to accurately predict the Young’s modulus and plastic stress–strain response of all different specimens in a wide temperature range. It is concluded that the differences in the mechanical response observed can be fully attributed to the changes induced by the SLM process in the polycrystalline microstructure, in particular the texture and grain aspect ratios. The accuracy of the model for all temperatures considered confirms that the polycrystalline microstructure was insensitive to temperature changes in the range considered, between 298 K and 1023 K.