Journal of Materials Research and Technology (May 2024)
Analysis of mechanical properties, microstructure, surface oxygen concentration and depth distribution of different heat-treated additive manufactured Ti–6Al–4V
Abstract
Laser-based additive manufacturing (AM) of Ti–6Al–4V alloy has garnered increasing significance for its application in components within transportation systems. A notable advantage over conventional steel structures lies in the reduction of specific weight. Employing a layer-by-layer manufacturing approach enables the production of complex geometries, facilitating faster and cost-effective personalized part manufacturing with reduced material waste compared to conventional methods. Post-processing plays a crucial role between the AM process and the utilization of the part, influencing its strength properties and porosity. Heat treatment emerges as a viable option to alter the final part's properties. Despite its advantages, the AM of Ti–6Al–4V parts is still a rather expensive technology because of the costs of equipment, materials and postprocessing. Postprocessing (surface and heat treatment) cannot be avoided for cost reduction since the mechanical properties of the as-printed state are not favourable for the applications. However, we can decrease the costs of manufacturing by the reduction of auxiliaries for example the use of inert gas during annealing. The question that we expect an answer to from our investigation is whether there are any significant differences in mechanical properties between heat treatment in an inert atmosphere or without protection. Another question is that in the case of annealing without an inert atmosphere, the used micro-glass blasting is suitable for removing the oxide layer. The mechanical examinations covered conventional tensile tests and hardness measurements. The depth distribution of oxygen was investigated by Glow Discharge Optical Emission Spectrometry (GDOES) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (EDS).
