E. Galieva, E. Klassman, R. Gabbasov, Egor M. Stepukhov, V. Valitov
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引用次数: 0
Abstract
It is shown that thermomechanical treatment (TMT) of the EK61 superalloy with a strain rate (ε ∙ ) of 10 −3 s −1 and a gradual decrease in the treatment temperature from (0.92 – 0.65) T δ leads to the transformation of the initial coarse-grained structure into an ultrafine-grained (UFG) mixed type structure. Such a mixed UFG microstructure consists of γ-phase grains and δ-phase particles 0.3 μm in size and relatively large particles of the δ-phase up to 2 μm in size. The EK61 superalloy having such a microstructure exhibits low-temperature superplasticity in the temperature range of 700 – 900°C, the maximum characteristics of which are achieved at 850°C and ε ∙ =10 −3 s −1 . Low-temperature TMT in the temperature range of (0.84 – 0.8) Т γ' also leads to the formation of an UFG structure in the EP975 superalloy. The UFG microstructure of the EP975 superalloy consists of γ-phase grains and γ'-phase particles 0.5 μm in size. And there are relatively large particles of the γ'-phase up to 3.5 μm in size of a globular-shaped form. The EP975 superalloy with such a structure exhibits low-temperature superplasticity in the temperature range of 900 –1000°C, the maximum characteristics of which are achieved at 1000°C and ε ∙ =10 −3 s −1 .
期刊介绍:
The aim of "Letters on materials" is to provide a fast publication of short research and review articles on various topics in materials science and related areas of material physics and mechanics. The editorial board sees it''s own task in rapid informing of the readers on the state-of-the-art challenges and achievements in materials science. The editorial board does its best to select high quality papers reporting new scientific results that are of interest for researchers in materials science, physics, and mechanics. "Letters on materials" invites Russian and foreign researches to publish papers in both the Russian and English languages. The scope of the journal covers the following research areas: structure analysis of materials, mechanical and physical properties of materials, production and processing of materials, experimental methods of investigation of materials, theory and computational methods in solid state physics. "Letters on materials" is designed for researchers, engineers, lecturers, and students working in the areas of materials science, mechanical engineering, metal forming, physics, and material mechanics.