Towards a Constitutive Model That Encapsulates Microstructural Features Induced by Powder Additive Manufacturing

The microstructural characteristics of materials processed via powder-based additive manufacturing (PAM) methods can be significantly different from those made by conventional manufacturing process using the same material. In an effort to link PAM process parameters with the functional performance of manufactured part, it is necessary to identify the effect of the special microstructural features generated by PAM on the final constitutive response of the relevant materials. In the present study, a microstructure-informed constitutive model is developed to describe the mechanical behavior of solidified material produced by PAM processes. The model is based on crystal plasticity and accounts for the effect of grain size and aspect ratio of the microstructure. The effect of these dominant features is captured by considering a core and mantle configuration for the grain volume, and by introducing a grain boundary influence region. The constitutive model’s ability to capture the grain size and shape effect is demonstrated by simulating the stress-strain behavior under uniaxial loading of a representative volume element (RVE) with columnar microstructure characterized by a range of grain sizes and aspect ratios.