Author:

Keywords:

Additive Manufacturing, Mechanical Properties, Microstructure, Preheating, Residual Stress, Selective Laser Melting, Ti6Al4V

Abstract:

Ti6Al4V parts produced by Selective Laser Melting need to undergo post process heat treatments for two reasons. The first is to relieve the residual stresses and the second is to transform the martensitic α’ microstructure to a more ductile mixture of α+β. The extra process step increases the price and lead time, while the latter is one of the benefits of producing parts with Additive Manufacturing. This research shows that preheating the base plate up to 400°C reduces residual stress by 50% and induces the presence of β phase in the final microstructure. However, excessive pickup of oxygen and nitrogen at high preheating temperatures reduced rather than increased the ductility. With the necessary hardware adaptations, preheating can be a useful tool to eliminate the need for post process heat treatments.