Kinetic Model of Thermoelastic Martensite Transformation in Niti and NiMn Based Shape Memory Alloys

1995 ◽  
Vol 398 ◽  
Author(s):  
K. H. Wu ◽  
J.D. Shi ◽  
F. Yang ◽  
Z. J. Pu
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Quantitative Model ◽  
Proposed Model ◽  
Series Of Experiments ◽  
The Relationship ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTA new, quantitative model was developed to describe the martensite transformation kinetics of thermoelastic shape memory alloys (SMAs). In addition, a series of experiments were conducted to study the Kinetics of thermoelastic martensite transformation in four SMA systems: NiTi, NiTi-15at%Hf, NiTi-20at%Zr and NiMn-7.5at%Ti alloys. Comparisons between data of the kinetic of martensite transformation with the present theoretic models show that the proposed model is in good agreement and concurs with the experimental data. Also, a comparison of data from the proposed model with data from existing kinetic models, such as Liang's and Magee's [1,7], indicates that the proposed model can better describe the experimental data, including the relationship between dξ(T)/dT and ξ, and dξ(T)/dT and T.

A New Continuous Model of Shape Memory Alloys

2012 ◽  
Vol 226-228 ◽  
pp. 2467-2470
Author(s):  
Wei Wang ◽  
Shi Yan
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Dynamic Loading ◽  
Continuous Model ◽  
Structure Control ◽  
Proposed Model ◽  
Loading System ◽  
Series Of Experiments ◽  
Continuous Dynamic ◽  
The Relationship

In this paper a new one-dimensional continuous model was proposed for Shape Memory Alloys (SMAs), which can be applied in the continuous dynamic loading system. After a literature review over the constitutive modeling of SMAs, an improved continuous model considering the influences of the various strain rates of SMAs was developed, which based on a series of experiments. The results of the experiments were used to validate the effectiveness of the proposed model. The constant factors in the model were determined according to the measured experimental data. The parameters in the model were also numerically analyzed and the numerical results matched well with experimental results. The results of the simulation showed that the developed model can effectively represented the relationship between the strain and stress of SMAs under dynamic loading and can be better applied in structure control.

Study of Two-Way Shape Memory Behavior of Amorphous-Crystalline TiNiCu Melt-Spun Ribbons

2013 ◽  
Vol 738-739 ◽  
pp. 352-356 ◽  
Author(s):  
Alexander Shelyakov ◽  
Nikolay Sitnikov ◽  
Sergey Saakyan ◽  
Alexey Menushenkov ◽  
Razhudin Rizakhanov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Melt Spinning ◽  
Shape Recovery ◽  
Electrochemical Polishing ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
The Relationship ◽  
Melt Spinning Technique

Recently we reported on the development of a composite material exhibiting reversible shape memory effect. A Ti–25Ni–25Cu (at.%) alloy was obtained by the melt spinning technique as amorphous–crystalline ribbons with a thickness of approximately 40 μm. The thickness of the amorphous and crystalline layers (dа and dc, respectively) was varied by electrochemical polishing. It has been ascertained that with varying the relationship dc/dа the martensite transformation and shape-recovery temperatures do not actually change, while the minimum radius of the ribbon bending decreases from 8.0 mm to 2.4 mm with increasing the relationship dc/dа from 0.33 to 1.40. The maximum reversible strain comprises 0.4% at dc/dа = 0.82. On the basis of experimental data obtained the phenomenological description, providing an explanation for nature of the phenomena taking place in the rapidly quenched amorphous-crystalline ribbon composite, has been proposed.

scholarly journals A Model to Describe the Magnetomechanical Behavior of Martensite in Magnetic Shape Memory Alloy

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Zaoyang Guo ◽  
Haitao Li ◽  
Qiang Wan ◽  
Xianghe Peng ◽  
Jing Wen
Keyword(s):  
Experimental Data ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Constitutive Behavior ◽  
Magnetic Shape Memory ◽  
Hyperbolic Tangent ◽  
Magnetic Shape Memory Alloy ◽  
Proposed Model ◽  
Pseudoelastic Behavior ◽  
Good Agreement

A model to describe the constitutive behavior of magnetic shape memory alloy composed with pure martensite is proposed based on the analysis of variants reorientation. A hyperbolic tangent expression is given to describe the variants transition during magnetic and mechanical loading process. The main features of magnetic shape memory alloy, such as pseudoelastic and partially pseudoelastic behavior as well as minor hysteretic loops, can be successfully replicated with the proposed model. A good agreement is achieved between calculated results and experimental data for NiMnGa single crystal.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

A phenomenological model for thermally-induced hysteresis in polycrystalline shape memory alloys with internal loops

2021 ◽  
pp. 1045389X2110482
Author(s):  
Yuxiang Han ◽  
Haoyuan Du ◽  
Linxiang Wang ◽  
Roderick Melnik
Keyword(s):  
Shape Memory Alloys ◽  
Single Crystal ◽  
Shape Memory ◽  
Phenomenological Model ◽  
Landau Theory ◽  
Thermally Induced ◽  
First Order ◽  
Proposed Model ◽  
Crystal Model ◽  
Hysteretic Response

In the current study, a 1-D phenomenological model is constructed to capture the temperature-induced hysteretic response in polycrystalline shape memory alloys (SMAs). The martensitic and austenitic transformations are regarded as the first-order transitions. A differential single-crystal model is formulated on the basis of Landau theory. It is assumed that the transformation temperatures follow the normal distribution among the grains due to the anisotropic stress field developed in the material. The polycrystalline hysteretic response is expressed as the integration of single-crystal responses. Besides, the prediction strategy for incomplete transitions is presented, and the first-order reversal curves are obtained via density reassignment. The proposed model is numerically implemented for validation. Comparisons between the modeling results and the experimental ones demonstrate the capability of the proposed model in addressing the hysteresis in thermally-induced phase transformations.

scholarly journals Microstructure and Phase Transformation Analysis of Ni50−xTi50Lax Shape Memory Alloys

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 345 ◽  
Author(s):  
Weiya Li ◽  
Chunwang Zhao
Keyword(s):  
Phase Transformation ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Martensite Transformation ◽  
Transformation Behavior ◽  
Ni Content ◽  
Start Temperature

The microstructure and martensitic transformation behavior of Ni50−xTi50Lax (x = 0.1, 0.3, 0.5, 0.7) shape memory alloys were investigated experimentally. Results show that the microstructure of Ni50−xTi50Lax alloys consists of a near-equiatomic TiNi matrix, LaNi precipitates, and Ti2Ni precipitates. With increasing La content, the amounts of LaNi and Ti2Ni precipitates demonstrate an increasing tendency. The martensitic transformation start temperature increases gradually with increasing La content. The Ni content is mainly responsible for the change in martensite transformation behavior in Ni50−xTi50Lax alloys.

Study of Donor Centres in n-InSb due to the Temperature Annealing

2005 ◽  
Vol 480-481 ◽  
pp. 197-200
Author(s):  
Y. Sayad ◽  
A. Nouiri
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Theoretical Study ◽  
Donor Concentration ◽  
Model Based ◽  
Proposed Model ◽  
Kinetics Of ◽  
Best Fit

An increasing of donor centres has been detected in n-InSb when it was submitted to anneal/quench with various annealing temperature (450 °C - 850 °C) and various annealing time (5 - 100 hours). A theoretical study of the kinetics of the conduction conversion of n-InSb at temperature annealing above 250 °C has been made. The present analysis indicates that the donor concentration increases with increasing of annealing time. In order to study this variation and to give a model for donor centres generated, a proposed model based on the simple kinetic is used to fit the variation of donor concentration as a function of annealing time. However, from the best fit of experimental data using the proposed model, the activation energy is determined.

scholarly journals Modelling the Characteristics of Ring-Shaped Magnetoelastic Force Sensor in Mohri’s Configuration

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 266 ◽  
Author(s):  
Anna Ostaszewska-Liżewska ◽  
Roman Szewczyk ◽  
Peter Raback ◽  
Mika Malinen
Keyword(s):  
Experimental Data ◽  
High Sensitivity ◽  
Force Sensor ◽  
Inhomogeneous Distribution ◽  
The Finite Element Method ◽  
The Core ◽  
Magnetoelastic Effect ◽  
Proposed Model ◽  
Distribution Of Stresses ◽  
Good Agreement

Magnetoelastic force sensors exhibit high sensitivity and robustness. One commonly used configuration of force sensor with a ring-shaped core was presented by Mohri at al. In this configuration force is applied in the direction of a diameter of the core. However, due to inhomogeneous distribution of stresses, model of such sensor has not been presented yet. This paper is filling the gap presenting a new method of modelling the magnetoelastic effect, which is especially suitable for the finite element method. The presented implementation of proposed model is in good agreement with experimental data and creates new possibilities of modelling other devices utilizing magnetoelastic effect.

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