Анизотропия деформации памяти формы в монокристалле сплава Ni-=SUB=-49-=/SUB=-Fe-=SUB=-18-=/SUB=-Ga-=SUB=-27-=/SUB=-Co-=SUB=-6-=/SUB=-

Stress-strain behavior of a cubic-shaped Ni49Fe18Ga27Co6 shape memory single crystal uniaxially compressed in three directions perpendicular to its faces was studied. The crystallographic orientation of the sample was chosen so that the sample was deformed along two <110>А and one [001]А directions. A fundamentally different stress-strain behavior was observed for the deformations along <110>A and [001]A directions. At room temperature, irrespective of the magnitude of the phase strain, the crystal compressed in [001]A exhibited superelastic behavior i.e. the strain fully recovered after unloading. In contrast, deformation along <110>A directions to the strain levels above 4% induced a residual shape memory strain after the unloading. Strains measured along the directions perpendicular to the compression axis indicate an anomalous behavior of the Poisson's ratio.

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Preliminary Investigations of a High Temperature Cu-13.3%Al-4%Ni Shape Memory Alloy Single Crystal

Applied Mechanics and Biomedical Technology ◽

10.1115/imece2003-42904 ◽

2003 ◽

Author(s):

Steve Trigwell ◽

Ganesh Kumara K. ◽

Abhijit Bhattacharyya ◽

Muhammed A. Qidwai

Keyword(s):

Plastic Deformation ◽

Shape Memory Alloy ◽

Single Crystal ◽

Shape Memory ◽

Room Temperature ◽

Alloy Single Crystal ◽

Stress Strain ◽

Stress Cycling ◽

Constitutive Response ◽

Martensite Reorientation

Preliminary investigations on the constitutive response of a Cu-13.3%Al-4%Ni (wt%) shape memory alloy single crystal with stress-free transformation temperatures around 100 to 150°C are reported. Room temperature stress cycling tests were carried out at very low deformation rates. Reproducible stress/strain curves of up to 9% strain due to detwinning (martensitematensite phase transformations) with no plastic deformation were obtained. The data also indicated that a period of stress cycling is required to stabilize the material before reproducible stress-strain curves are obtained due to martensite reorientation.

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Stress-strain behavior of Cu-Al-Ni single-crystal shape memory alloy at high temperature: shape memory effects

10.1117/12.539558 ◽

2004 ◽

Author(s):

Ganesh K. Kannarpady ◽

Steve Trigwell ◽

Abhijit Bhattacharyya ◽

Ivan Viahhi ◽

Sergei Pulnev

Keyword(s):

High Temperature ◽

Shape Memory Alloy ◽

Single Crystal ◽

Shape Memory ◽

Memory Effects ◽

Crystal Shape ◽

Stress Strain ◽

Strain Behavior ◽

Shape Memory Effects

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Anomalous stress-strain behavior of NiTi shape memory alloy close to the border of superelastic window

Scripta Materialia ◽

10.1016/j.scriptamat.2021.114135 ◽

2021 ◽

Vol 204 ◽

pp. 114135

Author(s):

Xiebin Wang ◽

Xiayang Yao ◽

Dominique Schryvers ◽

Bert Verlinden ◽

Guilong Wang ◽

...

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Niti Shape Memory Alloy ◽

Stress Strain ◽

Strain Behavior

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Thermal Processing of Polycrystalline NiTi Shape Memory Alloys

MRS Proceedings ◽

10.1557/proc-855-w1.9 ◽

2004 ◽

Vol 855 ◽

Author(s):

Carl P. Frick ◽

Alicia M. Ortega ◽

Jeff Tyber ◽

Ken Gall ◽

Hans J. Maier ◽

...

Keyword(s):

Heat Treatment ◽

Shape Memory ◽

Hot Rolling ◽

Rolling Process ◽

Heat Treatments ◽

Treatment Temperature ◽

Precipitate Size ◽

Stress Strain ◽

Transformation Temperatures ◽

Strain Behavior

ABSTRACTThe objective of this study is to examine the effect of heat treatment on polycrystalline Ti-50.9 at.%Ni subsequent to hot-rolling. In particular we examine microstructure, transformation temperatures and mechanical behavior of deformation processed NiTi. The results constitute a fundamental understanding of the effect of heat treatment on thermal/stress induced martensite, which is critical for optimizing mechanical properties. The high temperature of the hot-rolling process caused recrystallization, recovery, and hindered precipitate formation, essentially solutionizing the NiTi. Subsequent heat treatments were carried out at various temperatures for 1.5 hours. Transmission Electron Microscopy (TEM) observations revealed that Ti3Ni4 precipitates progressively increased in size and changed their interface with the matrix from being coherent to incoherent with increasing heat treatment temperature. Accompanying the changes in precipitate size and interface coherency, transformation temperatures were observed to systematically shift, leading to the occurrence of the R-phase and multiple-stage transformations. Room temperature stress-strain tests illustrated a variety of mechanical responses for the various heat treatments, from pseudoelasticity to shape memory. The changes in stress-strain behavior are interpreted in terms of shifts in the primary martensite transformation temperatures, rather then the occurrence of the R-phase transformation. The results confirm that Ti3Ni4 precipitates can be used to elicit a desired isothermal stress-strain behavior in polycrystalline NiTi.

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Stress–strain behavior of porous Ni–Ti shape memory intermetallics synthesized from powder sintering

Intermetallics ◽

10.1016/s0966-9795(99)00140-5 ◽

2000 ◽

Vol 8 (5-6) ◽

pp. 643-646 ◽

Cited By ~ 63

Author(s):

Bing-Yun Li ◽

Li-Jian Rong ◽

Yi-Yi Li

Keyword(s):

Shape Memory ◽

Stress Strain ◽

Strain Behavior ◽

Powder Sintering

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607 Stress-strain behavior of ultra fine Nitinol shape memory alloy wires

The Proceedings of Conference of Hokkaido Branch ◽

10.1299/jsmehokkaido.2009.48.189 ◽

2009 ◽

Vol 2009.48 (0) ◽

pp. 189-190

Author(s):

Makoto Kimata ◽

Hiroyuki KATO ◽

Kazuaki SASAKI

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Stress Strain ◽

Strain Behavior

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THE USE OF SHAPE-MEMORY ALLOYS FOR MECHANICAL REFRIGERATION

Functional Materials Letters ◽

10.1142/s1793604709000594 ◽

2009 ◽

Vol 02 (02) ◽

pp. 73-78 ◽

Cited By ~ 41

Author(s):

LLUÍS MAÑOSA ◽

ANTONI PLANES ◽

EDUARD VIVES ◽

ERELL BONNOT ◽

RICARDO ROMERO

Keyword(s):

Shape Memory Alloys ◽

Single Crystal ◽

Shape Memory ◽

Large Temperature ◽

Martensitic Transition ◽

Stress Strain ◽

Temperature Changes ◽

Entropy Changes ◽

Elastocaloric Effect ◽

Different Temperatures

This letter reports on stress–strain experiments on a Cu – Zn – Al single crystal performed using a purpose-built tensile device which enables the load applied to the specimen to be controlled while elongation is continuously monitored. From the measured isothermal tensile curves, the stress-induced entropy changes are obtained at different temperatures. These data quantify the elastocaloric effect associated with the martensitic transition in shape-memory alloys. The large temperature changes estimated for this effect, suggest the possibility of using shape-memory alloys as mechanical refrigerators.

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