Abstract
We draw upon existing knowledge of twinning and slip mechanics to develop a diffraction analysis model that allows for empirical quantification of individual deformation mechanisms to the macroscopic behaviors of low symmetry and phase transforming crystalline solids. These methods are applied in studying elasticity, accommodation twinning, deformation twinning, and slip through neutron diffraction data of tensile and compressive deformations of monoclinic NiTi to ~18% true strain. A deeper understanding of tension-compression asymmetry in NiTi is gained by connecting crystallographic calculations of polycrystalline twinning strains with in situ diffraction measurements. Our analyses culminate in empirical, micromechanical quantification of individual elastic, accommodation twinning, deformation twinning, and slip contributions to the total macroscopic stress-strain response of a monoclinic material subjected to large deformations. From these results, we find that 20-40% of the total plastic response at high strains is due to deformation twinning and 60-80% due to slip.
Original language | English (US) |
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Pages (from-to) | 2302-2330 |
Number of pages | 29 |
Journal | Journal of the Mechanics and Physics of Solids |
Volume | 61 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2013 |
Funding
This work has benefited from the use of the Lujan Neutron Scattering Center at LANSCE, which is funded by the Office of Basic Energy Sciences of the Department of Energy under DOE Contract DE-AC52-06NA25396. A.S. acknowledges funding through fellowships from the Toshio Mura Endowment, Predictive Science and Engineering Design Cluster at Northwestern (PSED), Initiative for Sustainability and Energy at Northwestern (ISEN). A.S. and C.B. acknowledge the support of the Army Research Office , Grant # W911NF-12-1-0013/P00002 , and A.G. and R.D.N. acknowledge support from the NASA Fundamental Aeronautics Program , Aeronautical Sciences Project. G.B. Olson is thanked for pre-submission critique of this work.
Keywords
- Monoclinic
- Neutron diffraction
- Plasticity
- Shape memory alloy
- Twinning
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering