Product Code: ICAL06_2005

Finite Element Analysis of Laser Powder Deposition of Titanium
Authors:
Antonio Crespo, Instituto Superior Tecnico; Lisbon Portugal
Augusto Deus, Instituto Superior Tecnico ; Lisbon Portugal
Rui Vilar, Instituto Superior Tecnico; Lisbon Portugal
Presented at ICALEO 2006

A three-dimensional finite element thermo-kinetic model was used to study phase transformations in laser melting and laser powder deposition of grade II commercially pure titanium. The model was validated for the case of surface treatment, by matching experimental and modeling results, namely on the location of melting and allotropic transformation isotherms for a range of processing parameters, allowing the estimation of an effective energy absorption coefficient for the experimental process. The model was then used to analyse the deposition of single tracks and to study the temperature as well as the phase proportions evolution along the deposition path as a function of the thermal cycle. Besides straight linear tracks, sharp and smooth corners are also featured, allowing for prediction of parameter adjustment in such critical zones. Additional features of the model include the curved shape of the single deposited tracks as well as discrete activation of successive elements to simulate the deposition process, and it can be straightforwardly extended to overlap and/or wall buildup conditions. Such model can be used to obtain the process parameter window for laser assisted deposition of pure titanium for a part of arbitrary deposition shape, while obeying a given set of desired microstructural requirements.