High-temperature failure and microstructural investigation of wire-arc additive manufactured Rene 41

Abstract In developing a wire-arc plasma direct energy deposition process for creep-resistant alloys used in high-speed flight applications, structures were built from nickel-based superalloy Rene 41. Samples of additive manufacturing (AM) material analysed their microstructural and mechanical properties, both as-deposited (AD) heat-treated (HT) conditions. Tensile specimens tested at room temperature, 538, 760, 1000 °C. Macroscopically, large columnar grains made up typical dendritic structure observed. Microscopically, significant segregation heavier elements, grain boundary precipitates, secondary phases observed, with key differences observed HT material. There was clear distinction between failure modes different testing temperatures AD variants. A fractographic investigation found progressive move brittle to ductile fracture increasing temperature conditions, as well features which support this observation.