Experimental investigation of Ti-6Al-4V microstructure and mechanical properties after laser powder bed fusion (LPBF) manufacturing and post-processing

Laser powder bed fusion (LPBF) is an additive manufacturing method that uses a laser to melt and consolidate powder materials layer by layer to build up 3D parts, making complex geometrical components possible in a minimally wasteful manner. Numerous industries are interested in utilising this manufacturing technique as a viable option to manufacture some of their components because of its potential to produce highly complex parts with minimal waste and excellent mechanical properties making it an attractive option for a wide range of applications, the aerospace and biomedical industries having a particular interest in using Ti-6Al-4V produced using LPBF.

Despite this, Ti-6Al-4V produced using LPBF often shows porosity, large residual stresses, rough surfaces, and martensitic microstructures, leading to poor fatigue properties. This thesis aims to better understand the structure and properties of parts manufactured using the LPBF process so that the results of this study can be useful for various applications. The research aimed to examine fatigue behaviour, surface topography, and the locations of fatigue cracks on parts, as well as to study the microstructure and mechanical properties of those parts, and particularly the effects of heat and cold exposure.