MAX phase compounds offer an attractive mixture of ceramic–metallic properties due to their covalent ionic–metallic nature. Since their discovery, a great interest was attributed to their synthesis and potential applications, but the processing of pure compounds as coatings for industrial large-scale application is still considered a challenge. To date, a limited number of papers have evaluated the build-up of MAX phase coating by cold spray (CS), a novel cost-effective and productive spray technology used in both areas of research and industry. Employing CS, the hot gas-propelled material particles have ballistic impingement on a substrate where they undergo plastic deformation. Because of the brittleness, internal delamination, and limited deformability, the deposition of the pure MAX phase is rather challenging. This paper presents the building-up ability of dense MAX-phase coatings by CS with retained structures and compositions, in close relation with the substrate characteristics and phase composition that influences the dual character ceramic–metallic behaviour. Besides recent literature, the originality of this research consists of pioneering deposition of Ti₃AlC₂ that emphasizes the ceramic–metallic character influenced by the particle speed and the mechanical properties of both substrate and compound.

Scaling up the production of TiAl turbine wheels for passenger car turbochargers requires the fabrication of thin blades that are similar to those of nickel-based superalloys. To achieve this, the molten metal fillability and impact resistance of thin blades must be improved. In this study, the effects of composition on these properties are predicted using simple laboratory experiments with binary, ternary, and practical alloys and are then verified with actual turbine wheels. The melt fillability of the turbine wheel blade is predicted using the amount of molten metal passing through an Al₂O₃-1%SiO₂ mesh. The binary alloy exhibits the best fillability, which is reduced by the addition of Cr and Si. Charpy impact tests on as-cast materials at 25 and 850 °C show that the addition of Cr and Mn improves the impact resistance, but the addition of Nb, W, Mo and Si reduces it. Therefore, the molten metal fillability and/or impact resistance of practical TiAl alloys containing such additives owing to other requirements are low and require improvement for use in thin-blade turbine wheel applications.

This work provides a comprehensive investigation into the synergistic effects of zirconium and oxygen on the microstructural evolution, high-temperature oxidation resistance, and mechanical properties of γ-phase Ti52AlxZr alloys (x = 0, 0.5, 1, and 2 at.%) under systematically controlled oxygen concentrations. Unlike prior studies that have examined these alloying elements in isolation, this study uniquely decouples the contributions of interstitial (oxygen) and substitutional (zirconium) solutes by employing low (LOx) and high (HOx) oxygen levels. Alloys were synthesized via vacuum arc melting and subsequently subjected to homogenization annealing at 1250 °C for 100 h to ensure phase and microstructural stability. Characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD) were employed to elucidate phase constitution and grain morphology. Zirconium addition was found to stabilize the γ-TiAl matrix, suppress α₂-phase formation, and promote grain coarsening in LOx specimens. Conversely, elevated oxygen concentrations led to α₂-phase precipitation along grain boundaries. Mechanical testing, comprising Vickers hardness and uniaxial compression at ambient and elevated temperatures (800 °C), revealed that both zirconium and oxygen significantly enhanced strength and hardness, with Ti52Al2Zr delivering optimal mechanical performance. Moreover, zirconium substantially improved oxidation resistance by promoting the formation of a thinner, adherent Al₂O₃ scale while simultaneously inhibiting TiO₂ growth. Collectively, the findings demonstrate the critical role of zirconium in engineering advanced γ-TiAl-based intermetallics with superior high-temperature structural integrity and oxidation resistance.

In the context of current climate issues and environmental constraints, green and renewable energies have experienced considerable growth in recent decades. Thus, there has been a renewed interest in the development of electric machines. To achieve this, the optimization of mass saving, volume and magnetic performance in the development of these machines must accelerate and be implemented industrially, particularly in the aeronautical field. The aircraft of the future will therefore require the use of electric machines with very high power densities and efficiencies. To achieve these objectives, one of the essential components to improve is the permanent magnet, and in particular its magnetic properties (increases in coercive field, residual magnetization and specific energy density). These magnets are likely to operate at temperatures above 200 °C. In this context, hard ferromagnetic magnets seem to be the most appropriate. SmCo₅ magnets have a Curie temperature between 720 and 920 °C. In this work we show the impact of grinding time on the magnetic properties of these SPS-treated magnets. This method allows the sintering SmCo₅ magnets while limiting their oxidation and their grain growth. By optimizing the grinding parameters, we obtain magnets with a coercive field of the order of 18,800 Oe. The novelty of this study lies in the optimization of EBSD (Electron Backscatter Diffraction) image analysis using the NLPAR (Non-Local Pattern Averaging Reconstruction) method, combined with advanced image correlation techniques. This approach enabled the precise determination of a grain size distribution centered around 50 nm, offering new perspectives on microstructural control and the enhancement of magnetic performance in SmCo₅ magnets.