Formation of deformation bands and precipitation of Ni 3 Al(γ′) phase in NiAl(β)-based single crystals by thermomechanical processing

摘要: Abstract Microstructure and crystal orientation distribution of two-phase NiAl(β)/Ni 3 Al(γ′) alloys obtained by thermomechanical processing were investigated. Cylindrical Ni-36 38 at.%Al alloy single crystals with various initial loading axes hot-compressed at a high strain rate 1.0 s −1 subsequently annealed in the (β/γ′) region. After hot deformation, relatively uniform subgrain structures formed 〈111〉 β -oriented crystals, while number deformation bands perpendicular to compressive axis developed 〈100〉 -, 〈110〉 - 〈123〉 crystals. Two types different orientations alternately arranged against axis. annealing region, film-shaped γ′ phase peculiar variants Kurdjumov–Sachs relationship preferentially precipitated along boundary between bands, resulting formation lamellar structure. Formation process crystallography precipitates discussed.