Order parameter evolution and Landau free energy coefficients for the B2↔R-phase transition in a NiTi shape memory alloy

2005 ◽  
Vol 14 (5) ◽  
pp. S192-S196 ◽  
Author(s):  
J Khalil-Allafi ◽  
W W Schmahl ◽  
T Reinecke
Keyword(s):  
Phase Transition ◽  
Free Energy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Order Parameter ◽  
Niti Shape Memory Alloy ◽  
Landau Free Energy

Modeling of Electrical Resistivity Evolution Using Free Energy Analysis for NiTi Shape Memory Alloy Wires

2011 ◽  
Vol 311-313 ◽  
pp. 2282-2285
Author(s):  
Jian Jun Zhang
Keyword(s):  
Electrical Resistivity ◽  
Free Energy ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Free Energy Change ◽  
Energy Change ◽  
Niti Shape Memory Alloy ◽  
Scanning Calorimetry ◽  
Proposed Model ◽  
Free Energy Analysis

This paper presents a transformation kinetics model of NiTi shape memory alloy (SMA) wires based on electrical resistivity (ER) derivative study under the assumption that the derivative of electrical resistivity with respect to temperature is in linear relationship with the derivative of free energy change with respect to temperature. Free energy change and electrical resistivity properties of SMA are analyzed based on differential scanning calorimetry (DSC) experiments during phase transformation. The simulated evolution of electrical resistivity during thermomechanical transformation is presented using the proposed model.

The role of phase transition in the fretting behavior of NiTi shape memory alloy

Wear ◽  
2005 ◽  
Vol 259 (1-6) ◽  
pp. 309-318 ◽  
Author(s):  
Linmao Qian ◽  
Zhongrong Zhou ◽  
Qingping Sun
Keyword(s):  
Phase Transition ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Niti Shape Memory Alloy

Dynamic Properties of NiTi Shape Memory Alloy under Combined Compression-Shear Loading

2014 ◽  
Vol 912-914 ◽  
pp. 7-11
Author(s):  
Qing Zheng Song ◽  
Zhi Ping Tang
Keyword(s):  
Phase Transition ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Shear Loading ◽  
Niti Shape Memory Alloy ◽  
Hopkinson Pressure Bar ◽  
Transition Points ◽  
Pressure Bar

The desired compression-shear loading were applied by the beveled ends with different angles, and this new technique based on split Hopkinson pressure bar can be used to investigate the dynamic response of materials. A series of experiments of NiTi shape memory alloy were performed at different impact velocities and different loading angles, and the dynamic equivalent pressure curves were given. The initial phase transition points under different impact velocities were plotted on σ-τ stresss space, and the phase transition surfaces predicted by a dynamic phase transition criterion were given.

Role of phase transition in the unusual microwear behavior of superelastic NiTi shape memory alloy

Wear ◽  
2006 ◽  
Vol 260 (4-5) ◽  
pp. 509-522 ◽  
Author(s):  
Linmao Qian ◽  
Qingping Sun ◽  
Xudong Xiao
Keyword(s):  
Phase Transition ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Niti Shape Memory Alloy

scholarly journals Mechanical Behaviour and Phase Transition Mechanisms of a Shape Memory Alloy by Means of a Novel Analytical Model

2018 ◽  
Vol 12 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Andrea Carpinteri ◽  
Vittorio Di Cocco ◽  
Giovanni Fortese ◽  
Francesco Iacoviello ◽  
Stefano Natali ◽  
...  
Keyword(s):  
Phase Transition ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Analytical Model ◽  
Testing Machine ◽  
Martensite Phase ◽  
Niti Shape Memory Alloy ◽  
Stress Strain ◽  
Dog Bone ◽  
Strain Relationship

Abstract The aim of the present paper is to examine both the fatigue behaviour and the phase transition mechanisms of an equiatomic pseudo-elastic NiTi Shape Memory Alloy through cyclic tests (up to 100 loading cycles). More precisely, miniaturised dog-bone specimens are tested by using a customised testing machine and the contents of both austenite and martensite phase are experimentally measured by means of X-Ray diffraction (XRD) analyses. On the basis of such experimental results in terms of martensite content, an analytical model is here formulated to correlate the stress-strain relationship to the phase transition mechanisms. Finally, a validation of the present model by means of experimental data pertaining the stress-strain relationship is performed.

Temperature Effect on the Friction Behavior of NiTi Shape Memory Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 780-783
Author(s):  
Lei Gong ◽  
Lin Mao Qian ◽  
Zhong Rong Zhou
Keyword(s):  
Phase Transition ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Friction Force ◽  
Niti Shape Memory Alloy ◽  
Temperature Dependent ◽  
Friction Behavior ◽  
Force Microscopy ◽  
Atomic Force ◽  
Simple Contact

By using an atomic force microscopy, the friction behavior of a NiTi shape memory alloy is investigated under various temperatures in vacuum environment. Under wearless condition at low loads, the adhesion-dominated friction of NiTi is almost temperature independent. However, while scratch mark appears after friction at high loads, the plough-dominated friction force is found to decrease with the increaase in temperature. Based on a simple contact analysis, the temperature dependent friction behavior of NiTi at high loads may be mainly attributed to the thermoelastic phase transition in NiTi. While temperature increases from 26~100°C, the tensile phase transition stress of NiTi increases from 412~964 MPa, which induces ~27% magnitude decrease in the contact area between the diamond tip and NiTi. It further results in the decrease in the plough-dominated friction force on NiTi.

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