Modeling of mechanical behavior in additive manufacturing at part scale

Abstract

Laser Beam Melting is actually capable of producing parts with reliable mechanical properties. However, efficient production still remains a challenge and high quality numerical simulation is required in order to understand the physical mechanisms involved. Consequently, a macroscopic numerical model at part scale is actually under development for understanding the relationship between different process and material parameters with the mechanical state of final parts such as distortion and residual stress. Classical finite element method is used to solve the coupled thermo-mechanical problem on the whole domain defined by the workpiece, the baseplate and the support structures. At this scale, powder packing is neglected as well as the hydrodynamics behavior within the melt pool. Homogeneous equivalent heat source is used and imposed until several layers below the current deposited layer. Elastoplastic constitutive material law with temperature dependent parameters has been developed.

High speed synchrotron X-ray diffraction experiments resolve microstructure and phase transformation in laser processed Ti-6Al-4V

“…A Pseudo-Voigt function was employed to fit the individual peaks. Timeresolved lattice spacings obtained from the fitting results were used to estimate temperature changes based on the reported coefficient of thermal expansion of Ti64 [17,31] using a method described in our previous research [29]. The estimation was not performed over the temperature range 800-1100°C where lattice changes could be impacted by the solid-state transformation.…”