Nano-twin-induced exceptionally superior cryogenic mechanical properties of a Ni-based GH3536 (Hastelloy X) superalloy

The GH3536 (Hastelloy X) superalloy is one of the most widely used Ni-based sheet alloys for gas turbine hot parts. To investigate its relationship among processing, microstructure, and mechanical properties, alloy was fabricated from pure constituent elements by arc melting drop casting. drop-cast ingots were homogenized, cold rolled, recrystallized to obtain single-phase microstructure with average grain size ∼12 μm. Tensile tests then performed at a wide temperature range between 77 K 1,073 K. Surprisingly, although this developed high use, it has extraordinary cryogenic properties. Moreover, yield strength, ultimate tensile elongation fracture increased dramatically decreasing temperature, exactly same behavior as that recently face-centered cubic medium/high-entropy (M/HEAs). Transmission electron microscopy study deformation mechanisms room temperature. Deformation-induced nano-twins observed after interrupted/fracture K, but rarely in specimens tested where plasticity occurred exclusively dislocation gliding. similarity 70-year-old M/HEAs, which considered revolution design, will be discussed viewpoint entropy calculation, mechanism.