Numerical simulation of laser powder deposition for TC15 titanium alloy brick parts

Abstract

Programming in ANSYS Parametric Design Language, finite element simulation was conducted for the fabrication of a TC15 titanium alloy brick part using laser powder deposition, which involves a multilayer and multitrack deposition process directed by the manoeuvring of a laser beam. The simulation entails modelling of the brick part by employing the ‘birth and death’ technique to tally with the additive manufacturing nature, and of the laser beam as a moving heat flux. The thermal stress is much stronger perpendicular to the scanning direction due to larger temperature gradient, and the Von Mises stress resides mainly in the centre of the top layer and along the circumferences of intermediate layers easily leading to fractures perpendicular to and parallel to the deposition surface respectively. Scanning along the long edge direction leads to much smaller stress, thus better quality, compared with scanning along the short edge direction, while in terms of stress there is little difference between unidirectional and back-and-forth scanning.