Directed Energy Deposition of the commercial intermetallic Ti-48Al-2Cr-2Nb alloy was investigated. The CLAD® process is dependent on multiple parameters, which were successfully optimised through several experiments, including series of beads, small blocks, and massive blocks, under argon atmosphere. The use of adapted temperature management leads to massive blocks manufacturing that bear no apparent macroscopic defects, such as cracks, which are generally observed in this brittle material due to strong temperature cycling during the manufacturing. The microstructure and geometrical parameters were characterised by scanning electron microscopy (SEM). This process generates an ultra-fine and anisotropic microstructure, which is restored to a homogeneous duplex microstructure by a subsequent heat-treatment. Mechanical characterisation is in progress and will be used to validate the soundness of the materials produced in these conditions.

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In this study, LMD-CLAD® process (Direct Laser Additive manufacturing) is developed for alumina and Al2O3-Y2O3-ZrO2ternary eutectic compositions. Powder flowability, laser-material interaction and thermal gradient control have been investigated. Powder granules of aforementioned compositions have been designed by spray-drying. Particle size distribution, Hall funnel test and SEM observations have been performed. Flowability has been improved by 20% in order to match with the LMD-CLAD® process by adjusting their density, size and surface quality. Otherwise, optical absorption of the ceramics has been increased up to 90% thanks to the addition of doping ions. With such a flowability improvement, laser powder deposition tests were successful and enabled us to investigate the effect of laser parameters and thermal environment on deposited beads state.