Microstructures and high-temperature tensile properties of a Co-Al-W-based superalloy prepared by laser additive manufacturing

Co-Al-W-based superalloys have a higher melting point than Ni-based superalloys, making them a promising new generation of superalloys for gas turbines. In this study, Co9Al9W—one of the most commonly used Co-Al-W-based superalloys—was investigated. Laser additive manufacturing technology was used to prepare the directionally solidified Co9Al9W. Single-track deposition experiments were conducted to explore the processing parameters that endow Co9Al9W with higher forming quality and better microstructure orientation. The geometry and dimensions of the single-track depositions and numerical simulations of the solidification conditions revealed that a high laser power and low scanning velocity were more conducive to the preparation of Co9Al9W with a directional microstructure. The microstructure of the Co9Al9W sample prepared using the selected processing parameters exhibited good orientation. Directionally solidified Co9Al9W after heat treatments exhibits good tensile properties at room and high temperatures, demonstrably better than those of as-cast Co-Al-W-based superalloys.