TY - GEN
T1 - Strain Rate Sensitivity of GH4720LI Alloy with Two Initial Microstructures During Hot Deformation
AU - Wan, Zhi Peng
AU - Wang, Tao
AU - Sun, Yu
AU - Hu, Lian Xi
AU - Li, Zhao
AU - Li, Peihuan
AU - Zhang, Yong
N1 - Publisher Copyright:
© 2019, Springer Nature Singapore Pte Ltd.
PY - 2019
Y1 - 2019
N2 - In this study, the effects of initial microstructure on the flow stress, strain rate sensitivity (m), and microstructure during hot deformation of GH4720LI alloy with different initial microstructures were studied using hot compression tests over a wide temperatures range of 1080–1180 °C and strain rates (0.001–10 s −1 ) to a final true strain of 0.8. The results showed that flow stress and deformation mechanisms of the alloys were significantly affected by the γ′ precipitates. The flow stresses of the two initial microstructures (i.e., microstructures AC and AF) presented typical DRX softening behavior and exhibited nearly a consistent variation trend which was decreased with the increase of temperature. The peak stresses in the microstructure of as-forged samples with smaller initial grain size were lower than microstructure AC when deformation temperature was lower than 1160 °C. While the gap between the two sets of specimens gradually decreased over a temperature of 1160 °C, which was mainly attributed to dissolution of the γ′ precipitates in alloys. According to the analysis of the strain rate sensitivity values distribution maps with two initial microstructures, the deformation mechanisms of the alloys in various deformation conditions were discussed in detail. Dislocation glide/climb was identified as the dominant deformation mechanism at low temperature, while grain boundary sliding and accommodation was confirmed as the main deformation mechanism at high temperature 1180 °C and low strain rate.
AB - In this study, the effects of initial microstructure on the flow stress, strain rate sensitivity (m), and microstructure during hot deformation of GH4720LI alloy with different initial microstructures were studied using hot compression tests over a wide temperatures range of 1080–1180 °C and strain rates (0.001–10 s −1 ) to a final true strain of 0.8. The results showed that flow stress and deformation mechanisms of the alloys were significantly affected by the γ′ precipitates. The flow stresses of the two initial microstructures (i.e., microstructures AC and AF) presented typical DRX softening behavior and exhibited nearly a consistent variation trend which was decreased with the increase of temperature. The peak stresses in the microstructure of as-forged samples with smaller initial grain size were lower than microstructure AC when deformation temperature was lower than 1160 °C. While the gap between the two sets of specimens gradually decreased over a temperature of 1160 °C, which was mainly attributed to dissolution of the γ′ precipitates in alloys. According to the analysis of the strain rate sensitivity values distribution maps with two initial microstructures, the deformation mechanisms of the alloys in various deformation conditions were discussed in detail. Dislocation glide/climb was identified as the dominant deformation mechanism at low temperature, while grain boundary sliding and accommodation was confirmed as the main deformation mechanism at high temperature 1180 °C and low strain rate.
KW - Deformation mechanism
KW - Hot compression test
KW - Initial microstructure
KW - Strain rate sensitivity
KW - γ′ precipitates
UR - https://www.scopus.com/pages/publications/85062102598
U2 - 10.1007/978-981-13-5944-6_27
DO - 10.1007/978-981-13-5944-6_27
M3 - 会议稿件
AN - SCOPUS:85062102598
SN - 9789811359439
T3 - Springer Proceedings in Physics
SP - 273
EP - 284
BT - Physics and Engineering of Metallic Materials - Proceedings of Chinese Materials Conference 2018
A2 - Han, Yafang
PB - Springer Science and Business Media, LLC
T2 - Chinese Materials Conference, CMC 2018
Y2 - 12 July 2018 through 16 July 2018
ER -