Irradiation-Induced Amorphization and Its Recovery Behavior in Cold-Rolled and Aged Ti-Ni Shape Memory Alloys

The ductility of Cu – Al – Mn shape memory alloys at room temperature depends on the aluminium content. High aluminium contents make Cu – Al – Mn very brittle and unsuitable for plastic shaping. Two Cu – Al – Mn shape memory alloys were investigated. The ductile alloy CuAl7.8Mn9.5 (all contents in wt. %) could be easily cold rolled by 86 %. The alloy CuAl12Mn4.3 could be cold rolled by only 12 - 14 %. The amplitude dependence of damping of austenitic specimens increased with increasing degree of cold work, whereas the damping of martensiticaustenitic specimens decreased. These observations can be explained by the creation of stress induced martensite and therefore by new moveable interfaces like phase- and twin boundaries, which contribute to damping. Plastic deformation increases the dislocation density, too. Both the increase of dislocation density and the increase of martensite content can lead to a decrease of damping mainly for high deformation degrees. Same shape memory alloys have shown negligible hardness increase during cold rolling, too. This behaviour, untypical for metals, can be explained by the generation of new martensite and by the fact that the hardness of martensite is smaller than the hardness of austenite. Some aging effects of the specimen after cold rolling, which lead to decrease of damping, were detected. This can be explained by pinning of moveable interfaces by point defects and/or retransformation of martensite into austenite.

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The Recovery Behavior of Quenched-In Vacancies in CuAlBe Shape Memory Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.105-110.1317 ◽

1992 ◽

Vol 105-110 ◽

pp. 1317-1320

Author(s):

Tian Min Wang ◽

Bao Yi Wang ◽

S.Y. Wang ◽

Y.Y. Dong ◽

Guo Zu Da

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Recovery Behavior

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Effect of Carbon Addition on Recovery Behavior of Trained FeMnSi Based Shape Memory Alloys

Advanced Engineering Materials ◽

10.1002/adem.201400193 ◽

2014 ◽

Vol 17 (2) ◽

pp. 205-210 ◽

Cited By ~ 8

Author(s):

Huabei Peng ◽

Jie Chen ◽

Shanling Wang ◽

Yuhua Wen

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Carbon Addition ◽

Recovery Behavior

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The Recovery Behavior of Quenched-in Vacancies in CuAlBe Shape Memory Alloys

phys stat sol (a) ◽

10.1002/pssa.2211290229 ◽

1992 ◽

Vol 129 (2) ◽

pp. K71-K75 ◽

Cited By ~ 2

Author(s):

T. M. Wang ◽

B. Y. Wang ◽

S. H. Zhang ◽

Y. Y. Dong ◽

G. Z. Da

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Recovery Behavior

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Recovery Behavior of Fe-Based Shape Memory Alloys under Different Restraints

Applied Sciences ◽

10.3390/app10103441 ◽

2020 ◽

Vol 10 (10) ◽

pp. 3441 ◽

Cited By ~ 2

Author(s):

Ki-Nam Hong ◽

Yeong-Mo Yeon ◽

Won-Bo Shim ◽

Do-Hyung Kim

Keyword(s):

Yield Strength ◽

Shape Memory Alloys ◽

Shape Memory ◽

Heating Temperature ◽

Experimental Results ◽

Recovery Stress ◽

Confining Stress ◽

Recovery Behavior ◽

Direct Tensile ◽

Direct Tensile Test

This paper presents the experimental results of an evaluation of the recovery behavior of Fe-based shape memory alloys (Fe-SMAs) under different restraints. For the study, three types of Fe-SMA (FSMA-A, FSMA-B, FSMA-C) were produced. As a result of the direct tensile test, the yield strength of the FSMA-A specimen was nearly 34% higher than the strength of FSMA-B and FSMA-C. Under free restraint, the recovery strains are 0.00956, 0.01445, and 0.01977 for FSMA-A, FSMA-B and FSMA-C specimens, respectively, after activation when the pre-strain is 0.04, and the heating temperature 200 °C. Under rigid restraint, the final recovery stresses are 518, 391 and 401 MPa for FSMA-A, FSMA-B, FSMA-C specimens after activation when a pre-strain of 0.04 and heating temperature 200 °C. Additionally, under the rigid restraint, the effect of pre-strain on the final recovery stress was insignificant, whereas the final recovery stress increased as the heating temperature increased. When Fe-SMA was constrained during cooling, the recovery stress is 50% lower than under rigid restraint. Hence, in order to develop a large recovery stress, Fe-SMA must be constrained during heating. In addition, a method for calculating the effective confining stress of the Fe-SMA coupler for pipe joining was proposed based on the experimental results.

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