EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Abstract

Nowadays, the production of complex components becomes more and more difficult due to its cost. In order to reduce the latter, companies tend to use additive manufacturing (AM). This technique consists of building the component layer upon layer. Many technologies of additive manufacturing can be used such as Electron Beam Melting (EBM), which is a powder bed fusion process that creates metallic parts with the aid of a beam source. However, defects are detected in parts after EBM. The aim of this study is to seal these defects using hot isostatic pressing (HIP) treatments, with regards to the mechanical properties (density, hardness, and microstructure). Three HIP were studied: standard HIP (T=950°C, P=1000 bars, t=2h), High-Temperature HIP (T=1050°C, P=1000 bars, t=2h), and 2 steps HIP (hold above the β-transus, rapid quenching, and tempering.). The different HIP seal internal porosity, but only the 2 steps Hip causes a columnar-to-equiaxed transition in the morphology of prior-β grains, changes the α lath aspect ratio, removes microstructural heterogeneities leading to a better match with the as-built condition.