This work investigates the microscopic deformation mechanisms of an extruded, precipitation-strengthened AZ80 magnesium (Mg) alloy subjected to strain-controlled low-cycle fatigue using in situ neutron diffraction measurements. Results demonstrate that the plastic deformation during cyclic loading is dominated by the alternating {10.2} extension twinning and detwinning mechanisms. The observed deformation mode is strongly texture and precipitate dependent. For the initial texture, the tested material has two major texture components which result in the occurrence of extension twinning during both compression and reverse tension in the first two cycles. The prolonged detwinning process in the following cycles is proposed to relieve the shear stress field of {00.2} grains, leading to the disappearance of twinning. The precipitation strengthening results in an increase of the critical resolved shear stress (CRSS) by similar to 33 MPa for the extension twinning in this AZ80 alloy. Here, the synergistic effects of the initial texture, precipitation strengthening, and load sharing of various grain families and phases contribute to the complicated evolution of dominant deformation mechanisms, among which elevated dislocation activities are believed to be responsible for the relatively poor low-cycle-fatigue lifetime when compared to other Mg alloys.
Xie, Di, et al. "In situ monitoring of dislocation, twinning, and detwinning modes in an extruded magnesium alloy under cyclic loading conditions." Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing, vol. 806, Jan. 2021. https://doi.org/10.1016/j.msea.2021.140860
Xie, Di, Lyu, Zongyang, Li, Yuan, Liaw, Peter K., Chew, Huck Beng, Ren, Yang, Chen, Yan, An, Ke, & Gao, Yanfei (2021). In situ monitoring of dislocation, twinning, and detwinning modes in an extruded magnesium alloy under cyclic loading conditions. Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing, 806. https://doi.org/10.1016/j.msea.2021.140860
Xie, Di, Lyu, Zongyang, Li, Yuan, et al., "In situ monitoring of dislocation, twinning, and detwinning modes in an extruded magnesium alloy under cyclic loading conditions," Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing 806 (2021), https://doi.org/10.1016/j.msea.2021.140860
@article{osti_1785086,
author = {Xie, Di and Lyu, Zongyang and Li, Yuan and Liaw, Peter K. and Chew, Huck Beng and Ren, Yang and Chen, Yan and An, Ke and Gao, Yanfei},
title = {In situ monitoring of dislocation, twinning, and detwinning modes in an extruded magnesium alloy under cyclic loading conditions},
annote = {This work investigates the microscopic deformation mechanisms of an extruded, precipitation-strengthened AZ80 magnesium (Mg) alloy subjected to strain-controlled low-cycle fatigue using in situ neutron diffraction measurements. Results demonstrate that the plastic deformation during cyclic loading is dominated by the alternating {10.2} extension twinning and detwinning mechanisms. The observed deformation mode is strongly texture and precipitate dependent. For the initial texture, the tested material has two major texture components which result in the occurrence of extension twinning during both compression and reverse tension in the first two cycles. The prolonged detwinning process in the following cycles is proposed to relieve the shear stress field of {00.2} grains, leading to the disappearance of twinning. The precipitation strengthening results in an increase of the critical resolved shear stress (CRSS) by similar to 33 MPa for the extension twinning in this AZ80 alloy. Here, the synergistic effects of the initial texture, precipitation strengthening, and load sharing of various grain families and phases contribute to the complicated evolution of dominant deformation mechanisms, among which elevated dislocation activities are believed to be responsible for the relatively poor low-cycle-fatigue lifetime when compared to other Mg alloys.},
doi = {10.1016/j.msea.2021.140860},
url = {https://www.osti.gov/biblio/1785086},
journal = {Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing},
issn = {ISSN 0921-5093},
volume = {806},
place = {United States},
publisher = {Elsevier},
year = {2021},
month = {01}}
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; National Science Foundation (NSF)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
1785086
Alternate ID(s):
OSTI ID: 1828467
Journal Information:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing, Journal Name: Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing Vol. 806; ISSN 0921-5093