Temperature and printing axis effects on anisotropic sintering in binder jetting additive manufactured 17-4 PH stainless steel: Experimental and numerical study

The effect of sintering temperature and printing orientation on anisotropic shrinkage in binder-jetted 17-4 PH stainless steel is investigated through a combined experimental and finite element modeling approach. Quasi-isotropic shrinkage is observed in the X–Y plane, while the Z-direction shows an anisotropic shrinkage ratio (ASR) up to 1.4, mainly due to primitive line collapse above 1250 °C when Grain boundary diffusion (Q = 100–125 kJ/mol) shifted to volume diffusion (Q = 250–320 kJ/mol). A similar activation energy was observed along the X, Y, and Z axes, but the transition temperature (1250 °C) is slightly higher than what is normally reported for conventional powder metallurgy (1000–1150 °C) due to carbon residue from the binder. Finite element simulations show higher shear (G = 12000 MPa s) and bulk (K = 26400 MPa s) modulus along the Z axis compared to the powder bed plane due to the directional pore distribution. As the temperature increases, pores become more homogenously distributed, leading to more isotropic shrinkage mechanisms and similar K and G values across the powder bed.