An integrated modeling of process-structure-property relationship in laser additive manufacturing of duplex titanium alloy

Abstract

A new heat source model is proposed for the simulation of the temperature rises in the laser deposition melting additive manufacturing process. The obtained temperature histories in different layers can be used to predict the microstructural evolutions in a multiscale strategy including the grain cluster scale and single grain scale in Monte Carlo model. It is found that re-melting and re-heating due to different temperature histories of different layers are main factors to affect the microstructural evolutions in LAM. By use of the predicted microstructural and the self-consistent model, the flow stresses at different strain rates and temperatures are predicted. The predicted flow stress shows that the flow stress is higher in the middle of the as-built LAM product but lower near the top or the bottom surfaces. The increase of the scanning speed of laser can lead to the increase of the size of heat affected zone, which is the reason for the formation of larger grain sizes and more α generations in higher scanning speed. Higher α volume fraction is the main reason for higher mechanical property in higher scanning speed.