Grain refinement and superplasticity of Inconel 718 processed by Multi-Pass High-Pressure sliding

• Published in: Materials letters Vol. 300; p. 130144
• Main Authors: Tang, Yongpeng, Edalati, Kaveh, Masuda, Takahiro, Takizawa, Yoichi, Yumoto, Manabu, Horita, Zenji
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2021; Elsevier BV
• Subjects: Elongation; Grain refinement; Grain size; Hardness measurement; Inconel 718; Materials science; Multi-pass high-pressure sliding; Nickel base alloys; Severe plastic deformation; Sliding; Strain rate; Superalloys; Superplasticity; Tensile tests; Ultrafines; Multi-pass high-pressure sliding; Superplasticity; Severe plastic deformation; Inconel 718; Grain refinement
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2021.130144

•Process of multi-pass high-pressure sliding was applied to rods of Inconel 718.•Grain refinement of the Inconel 718 was achieved with grain size of ~ 140 nm.•A homogeneous microstructure was developed throughout cross section by 45° rotation.•Inconel 718 after processing by MP-HPS with 45° rotation exhibited superplasticity.•The minimum rotation angle was estimated with respect to the rod diameter. Inconel 718 was successfully processed by multi-pass high-pressure sliding (MP-HPS) for production of ultrafine-grained structures in rods with upsized dimensions. An ultrafine-grained (UFG) structure with an average grain size of ~ 140 nm was developed through rotation of 45°. Tensile testing at 1073 K with an initial strain rate of 2x10-2 s−1 led to superplastic elongations more than 400%. A relation is established between hardness and elongation to failure so that it should be possible to predict the advent of superplasticity only from the hardness measurement.