TY  - SER
AU  - Paul,Partha P.
AU  - Amin-Ahmadi,Behnam
AU  - Sharma,Hemant
AU  - Dale,Darren
AU  - Ko,Jun Young Peter
AU  - Chumlyakov,Yuri I.
AU  - Brinson,L.Catherine
AU  - Stebner,Aaron Paul
AU  - Paranjape,Harshad M.
TI  - In situ, 3D characterization of the deformation mechanics of a superelastic NiTi shape memory alloy single crystal under multiscale constraint
KW  - фазовые превращения
KW  - сплавы с памятью формы
KW  - микроструктурные элементы
KW  - границы зерен
KW  - статьи в журналах
N1  - Библиогр.: 64 назв
N2  - Microstructural elements in NiTi shape memory alloys (SMAs) e precipitates, phase boundaries, inclusions,
grain boundaries e can be viewed as sources of multiscale constraint that influence their
 deformation response. We characterized in situ, and in 3D, the deformation and the evolution of
 microstructure during a tension test in a superelastic NiTi specimen containing some of these sources of
 constraint. The method used was far-field high-energy X-ray diffraction microscopy (ff-HEDM), complemented
 by electron microscopy. We simulated the local stress state in the specimen using a microstructural
 model informed by the experimental data. Using these combined microstructure, deformation,
 and stress data, we report three phenomena, and relate them to specific sources of constraint. During
 initial elastic loading, axial lattice strain in austenite increased monotonically. On partial stress-induced
 phase transformation to martensite, the stress redistributed to both phases leading to a stress relaxation
 in austenite. The specimen contained a dense distribution of inclusions, which led to the activation of
 martensite habit plane variants that produce less than theoretical maximum transformation strain. Large
 Ni4Ti3 precipitates potentially contributed to the poor transformation response. Under load, proportional
 gradients in local rotation and elastic stretch developed in the martensite phase, because of the
 constraint at phase interfaces. This combined ff-HEDM, electron microscopy, microstructural simulation
 toolbox provides a versatile method to understand the effect of constraint on inelastic deformation in
 other alloys with hierarchical microstructure
UR  - http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000653439
ER  -