An investigation into microstructure and high-temperature mechanical properties of selective laser-melted 316L stainless steel toward the development of hybrid Ampliforge process

The most prevalent hybrid additive manufacturing (HAM) method in the industry involves the combination of conventional processes, such as hot isostatic pressing or forging. In this way, a part is printed to its near-net-shape by additive manufacturing and then finished using open forge (Ampliforge). Hereby, the performance of the printed part will be improved by the downstream processes; this method also affords a reduction in time, cost, and waste material. In this study, the AISI 316L stainless steel parts were produced through selective laser melting (SLM) process and the cellular structure with columnar grains appeared. Then, hot compression experimental works were performed to investigate flow behavior, hot workability, density, and microstructure evolutions during the process. This process resulted in a near fully-dense part with a homogeneous microstructure without anisotropy of properties and higher hot deformation activation energy and peak stress in comparison with similar conventionally manufactured stainless steel.