Fig. 7: Mechanism of residual strain evolution.
From: Operando neutron diffraction reveals mechanisms for controlled strain evolution in 3D printing
Residual stain evolution depends on heating, cooling, and reheating during deposition of multiple build sections. On initial deposition, expansion during the FCC to BCC formation creates a compressive strain in the deposit and tensile strain in the substrate. During reheating, an FCC/BCC interface forms, at which the differential CTE and the FCC to BCC transformation on cooling create a localized compression/tension strain pattern. In addition, reheating of BCC below the interface creates an annealing affect that softens the material.
