Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7972412 | Materials Science and Engineering: A | 2018 | 8 Pages |
Abstract
Two types of hot compression tests, namely, constant strain rate and strain rate jump, were carried out for Alloy 800â¯H within a wide temperature range of 450-900â¯Â°C and strain rate range of 0.001-1â¯sâ1. Following the above tests, we studied the effect of dynamic strain aging (DSA) on the mechanical properties and microstructure features to reveal the underlying mechanism responsible for DSA. The results indicated that three kinds of serrated yielding behavior (Type A, B and C) can be observed in the stress-strain curves of the DSA regime. The DSA temperature (TDSA) is located in the temperature range of 500-750â¯Â°C at a strain rate of 0.001â¯sâ1, in 550-790â¯Â°C at 0.01â¯sâ1, and in 600-840â¯Â°C at 0.1â¯sâ1. The activation energy for the appearance of negative strain rate sensitivity was calculated to be 194â¯kJ/mol, and pipe diffusion of substitutional solutes (i.e. Cr, Ni and Ti) is regarded as the mechanism of DSA. TEM observations further elucidated a tendency of linear microstructure within the DSA regime, which also restricts the cross-slip of dislocations and promotes the strain localization along deformation bands.
Related Topics
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Authors
Yu Cao, Chenghang Zhang, Cheng Zhang, Hongshuang Di, Guangjie Huang, Qing Liu,