Thermal histories and microstructures in Direct Energy Deposition of a High Speed Steel thick deposit

The results of 2D Finite Element thermal simulations of Direct Energy Deposition of a High Speed Steel thick deposit explain the observed microstructural heterogeneities over the whole height of a 36-layer deposit. The Finite Element model is validated by the recorded substrate temperature and the melt pool depth of the last clad layer experimentally measured. The correlation between the computed thermal fields and the microstructures of three points of interest located at different depths within the deposit is carried out. The effect of both the melt superheating temperature and the thermal cyclic history on the carbides type, shape and size is discussed.