Transformation Sequence Rule of Martensite Plates and Temperature Memory Effect in Shape Memory Alloys

Liu, Tianwei; Zheng, Yubin; Cui, Lishan

doi:10.1007/s40195-015-0324-7

Cited by 5 publications

(2 citation statements)

References 18 publications

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“…Moreover, the temperature memory effect (TME) has been emphasized in Figure 6b after interrupting the first heating at 60 • C. TME occurred in the second heating under a characteristic form with two endothermic peaks. As expected, the interruption of the second cooling cycle did not cause any peak splitting [30]. Aiming to observe the eventual solid-state transitions that might occur during heating above the thermal range for reverse martensitic transformation, DSC experiments were performed up to 1200 • C on fragments cut from the opm specimens subjected to tensile tests, according to Figure 3.…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 76%

Structural-Functional Changes in a Ti50Ni45Cu5 Alloy Caused by Training Procedures Based on Free-Recovery and Work-Generating Shape Memory Effect

et al. 2022

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Active elements made of Ti50Ni45Cu5 shape memory alloy (SMA) were martensitic at room temperature (RT) after hot rolling with instant water quenching. These pristine specimens were subjected to two thermomechanical training procedures consisting of (i) free recovery shape memory effect (FR-SME) and (ii) work generating shape memory effect (WG-SME) under constant stress as well as dynamic bending and RT static tensile testing (TENS). The structural-functional changes, caused by the two training procedures as well as TENS were investigated by various experimental techniques, including differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X-ray diffraction (XRD), and atomic force microscopy (AFM). Fragments cut from the active regions of trained specimens or from the elongated gauges of TENS specimens were analyzed by DSC, XRD, and AFM. The DSC thermograms revealed the shift in critical transformation temperatures and a diminution in specific absorbed enthalpy as an effect of training cycles. The DMA thermograms of pristine specimens emphasized a change of storage modulus variation during heating after the application of isothermal dynamical bending at RT. The XRD patterns and AMF micrographs disclosed the different evolution of martensite plate variants as an effect of FR-SME cycling and of being elongated upon convex surfaces or compressed upon concave surfaces of bent specimens. For illustrative reasons, the evolution of unit cell parameters of B19′ martensite, as a function of the number of cycles of FR-SME training, upon concave regions was discussed. AFM micrographs emphasized wider and shallower martensite plates on the convex region as compared to the concave one. With increasing the number of FR-SME training cycles, plates’ heights decreased by 84–87%. The results suggest that FR-SME training caused marked decreases in martensite plate dimensions, which engendered a decrease in specific absorbed enthalpy during martensite reversion.

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Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 76%

Structural-Functional Changes in a Ti50Ni45Cu5 Alloy Caused by Training Procedures Based on Free-Recovery and Work-Generating Shape Memory Effect

et al. 2022

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“…(2), it is necessary to diminish the mechanical driving force for transformation from martensite to austenite so as to enhance the austenitic transformation start temperature A s . Therefore, the elastic strain energy stored in the martensite phase plays a significant role in the phase transformation of NiTi shape memory alloy [23]. In general, the conventional NiTiFe shape memory alloy is designed by replacing Ni element by Fe element to lower the martensitic transformation start temperature M s .…”

Section: Discussionmentioning

confidence: 99%

Influence of Fe Addition on Phase Transformation, Microstructure and Mechanical Property of Equiatomic NiTi Shape Memory Alloy

Zhao

Jiang

Zhang

et al. 2017

Acta Metall. Sin. (Engl. Lett.)

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Based on equiatomic nickel and titanium, three kinds of NiTiFe alloys with a nominal chemical composition of Ni 49 Ti 49 Fe 2 , Ni 48 Ti 48 Fe 4 and Ni 47 Ti 47 Fe 6 (at.%), respectively, have been designed to investigate the influence of the addition of Fe element on phase transformation, microstructure and mechanical property of equiatomic NiTi shape memory alloy. The microstructures of three kinds of NiTiFe alloys are characterized by the equiaxed grains instead of the dendrites. Consequently, some Ti 2 Ni precipitates are found to distribute in the grains interior and at the grain boundaries. The content of Fe element has an important influence on mechanical property of NiTiFe alloy. With increasing content of Fe element, the strength of NiTiFe alloy increases substantially, but the plasticity decreases sharply. It can be concluded that precipitation strengthening and solution strengthening play a significant role in enhancing the strength of NiTiFe alloy. In the case of three NiTiFe alloys, neither martensitic transformation nor reverse transformation can be observed in the range from-150 to 150°C. On the one hand, the phase transformation temperature is probably out of the scope of the present experimental temperature. On the other hand, the addition of Fe element probably suppresses first-order martensitic transformation or reverse transformation, and consequently the second-order-like phase transformation from an incommensurate stage to a commensurate stage can probably take place.

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Fabrication and characterization of Cu–Zn–Sn shape memory alloys via an electrodeposition–annealing route

Espiritu

Amorsolo

2019

Int J Miner Metall Mater

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Transformation Sequence Rule of Martensite Plates and Temperature Memory Effect in Shape Memory Alloys

Cited by 5 publications

References 18 publications

Structural-Functional Changes in a Ti50Ni45Cu5 Alloy Caused by Training Procedures Based on Free-Recovery and Work-Generating Shape Memory Effect

Structural-Functional Changes in a Ti50Ni45Cu5 Alloy Caused by Training Procedures Based on Free-Recovery and Work-Generating Shape Memory Effect

Influence of Fe Addition on Phase Transformation, Microstructure and Mechanical Property of Equiatomic NiTi Shape Memory Alloy

Fabrication and characterization of Cu–Zn–Sn shape memory alloys via an electrodeposition–annealing route

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