Chapter 2 - Effect of post-heat treatment on the properties of additive manufacturing parts

Abstract

Additive manufacturing (AMf) allows the production of complex sophisticated shapes and high-quality components with a great design freedom and customization. Amon the various techniques of AMf, selective laser melting (SLM), and electron beam melting (EBM) are the most popular powder bed fusion process having their potential in the fabrication of the metallic components. Due to high mechanical properties, low density, and high-melting point, Ti–6Al–4V alloys is a promising material that can be fabricated by using the powder bed fusion techniques of AM for aerospace industry. Because of excellent biocompatibility and low degradation, Ti–6Al–4V alloys have also been applied to many tissue engineering applications. The novelty of the recent study is the congregation of the data from the multiple research articles from last 20 to 25 years about the parts of Ti–6Al–4V alloys fabricated via SLM and EBM process. The information was gathered for the analysis of the residual stresses and influence of a variety of heat treatment processes on the part porosity and mechanical properties. In this work, the results reveal that the microstructure in both the process is different form the expectations, which is attributed to different cooling cycles. The results also show that microstructure of the titanium parts can be modified by heat treatment processes which can facilitates in reduction of residual stresses, improvement in the ductility as well as fatigue life, and enhancement of the component hardness. Furthermore, the present study confirms that discrete post-treatment technique can be developed for the induction of the compressive residual stresses and consequently, fatigue life can be improved.