Macroscopic shape change of Cu13Zn15Al shape memory alloy on successive heating

2008 ◽  
Vol 452 (2) ◽  
pp. 307-311 ◽  
Author(s):  
Z. Li ◽  
S. Gong ◽  
M.P. Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Change ◽  
Macroscopic Shape ◽  
Successive Heating

Crystallographic Characteristics of Shape Memory Alloys

2011 ◽  
Vol 1295 ◽  
Author(s):  
Madangopal Krishnan
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Change ◽  
Parent Phase ◽  
The Self ◽  
Intermetallic Alloys ◽  
Martensitic Microstructure ◽  
Crystallographic Characteristics ◽  
Macroscopic Shape ◽  
Microstructural Examination

ABSTRACTThe martensitic microstructure of shape memory alloys is an aggregate of self accommodating plate groups. The principal character of this aggregate is its demonstration of pseudoplasticity, wherein a macroscopic shape change is brought about by extensive rearrangement and reorientation of the self accommodating martensite variants, and that of microstructural reversibility, wherein the polyvariant microstructure transforms back to the original grain of the parent phase after pseudoplastic deformation. These aspects of the shape memory intermetallic alloys are intriguing and, to a great extent, unsolved. The aim of this paper is to show that the underlying crystallographic interrelationships of the self accommodating microstructure of intermetallic alloys are responsible for the observed effect. The paper will discuss the relation between autocatalytic nucleation and self accommodation, the relation between microstructural reversibility and intervariant interfaces of the martensitic microstructure and the manifestations of microstructural irreversibility using results from the microstructural examination of the self accommodating microstructures.

NiTi Shape Memory Alloy Active Element Behavior in Long Time Solicitation Conditions

2014 ◽  
Vol 657 ◽  
pp. 387-391
Author(s):  
Adela Ursanu Dragoş ◽  
Sergiu Stanciu ◽  
Ramona Cimpoeşu ◽  
Cristian George Adoroaie ◽  
Petronela Paraschiv ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Active Element ◽  
Shape Change ◽  
Niti Shape Memory Alloy ◽  
Potential Candidate ◽  
Joule Effect ◽  
Aerospace Applications ◽  
Before And After ◽  
Temperature Transformation

Equi-qtomic NiTi (nitinol) shape memory alloy (SMA) is a good potential candidate material for use as thermo-mechanical actuator in a large variety of engineering like automotive and aerospace applications. Shape memory alloy in action are required to perform a large number of actuation cycles under cyclic thermo-mechanical loads and therefor are subject of fatigue. A shape memory alloy, supplied from Nimesis Technology, with martensite to austenite temperature transformation domain 76-80 °C. The material characteristics were investigated through differential calorimetry (DSC) before and after the thermo-mechanical solicitations. Under Joule effect and a timer, the active element goes up to 3000 cycles with a 500g weight on. The properties of thermo-elastic martensite transformation are the elastic accommodation of volume and shape change that takes place due to change in crystal structure upon phase transformation. A modification of the first coil of the intelligent arch-wire suffer a modification of the temperature transformation domain increasing the As and Af temperature values.

scholarly journals Induction heating of a shape memory alloy beam

2018 ◽  
Vol 83 (3) ◽  
pp. 30905 ◽  
Author(s):  
S. Dufour ◽  
G. Vinsard
Keyword(s):  
Temperature Field ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Induction Heating ◽  
Mechanical Model ◽  
Eddy Currents ◽  
Shape Change ◽  
Nickel Titanium ◽  
Thin Shells ◽  
Induced Currents

The shape memory alloy heating by eddy currents is a quick solution for the shape change. Then, the analysis of the temperature field as a function of the shape is important to build a mechanical model in large deformation. Even if the temperature can be obtained by experiment, a computational model is useful. The computation of the induced currents in a nickel–titanium shape memory alloy beam is here considered with a T − Ω model adapted to thin shells with the help of a change of coordinates. It allows us to take into account the shape change, without the need of remeshing, as a function of the temperature. Experiments are carried out to validate the model.

Review of Self-Healing Effect on Shape Memory Alloy (SMA) Structures

2013 ◽  
Vol 701 ◽  
pp. 87-92 ◽  
Author(s):  
M.R. Hassan ◽  
M. Mehrpouya ◽  
Sattar Emamian ◽  
M.N. Sheikholeslam
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Materials Science ◽  
Shape Change ◽  
Initial Crack ◽  
Self Healing ◽  
Metallic Materials ◽  
A Minor ◽  
Almost All ◽  
Biological Organisms

Self-healing has usually an emphasis on special materials that is metallic materials. When there is a minor damage, almost all biological organisms, even complex ones, have the ability to repair themselves. Recently, a novel field of materials science is constituted by self-healing in organic materials or material systems and it is rapidly expanding. These materials have a particular ability to heal themselves. The initial crack is healed to the point that upon reloading, a new crack is formed next to the original, rather than the original crack reopening. Only simple heating can reverse transformation and cause reinforcement for these cracks. The shape memory alloy wires are activated by heating the system and therefore the healing begins. Due to the heat, the wires relapse to their original shape at the shape change in martensite to austenite transition temperature. The concentration of most of the studies so far has been on polymers and ceramics and the reason is that it includes self-healing in non-metallic materials. Also, they are more convenient than including it in metallic materials. In this review paper the design principles of self-healing materials and their improvement methods are investigated.

Aero-structural optimization of shape memory alloy-based wing morphing via a class/shape transformation approach

2017 ◽  
Vol 232 (15) ◽  
pp. 2745-2759 ◽  
Author(s):  
Pedro BC Leal ◽  
Marcelo A Savi ◽  
Darren J Hartl
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
High Performance ◽  
Optimization Problems ◽  
Shape Change ◽  
Shape Transformation ◽  
Baseline Design ◽  
Deformable Structure ◽  
Stall Angle ◽  
Wing Morphing

Because of the continuous variability of the ambient environment, all aircraft would benefit from an in situ optimized wing. This paper proposes a method for preliminary design of feasible morphing wing configurations that provide benefits under disparate flight conditions but are also each structurally attainable via localized active shape change operations. The controlled reconfiguration is accomplished in a novel manner through the use of shape memory alloy embedded skin components. To address this coupled optimization problem, multiple sub-optimizations are required. In this work, the optimized cruise and landing airfoil configurations are determined in addition to the shape memory alloy actuator configuration required to morph between the two. Thus, three chained optimization problems are addressed via a common genetic algorithm. Each analysis-driven optimization considers the effects of both the deformable structure and the aerodynamic loading experienced by the wing. Aerodynamic considerations are addressed via a two-dimensional panel method and each airfoil shape is generated by the so-called class/shape transformation methodology. It is shown that structurally and aerodynamically feasible morphing of a modern high-performance sailplane wing produces a 22% decrease in weight and significantly increases stall angle of attack and lift at the same landing velocity when compared to a baseline design that employs traditional control surfaces.

Use of shape memory alloy for active shock control bump application

2021 ◽  
pp. 1045389X2110386
Author(s):  
Jinhao Qiu ◽  
Lin Hao ◽  
Hongli Ji ◽  
Chen Zhang ◽  
Rui Nie
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Mechanical Response ◽  
Shape Change ◽  
Operating Conditions ◽  
Training Procedure ◽  
Scanning Calorimetry ◽  
Mechanical Responses ◽  
Shock Control Bump ◽  
Shock Control

A shape memory alloy (SMA) with composition of Ni50.1Ti49.9 (at. %) was used for fabrication of a 3-D bump structure intended for use as an active shock control bump (SCB) into a transonic wing. This kind of bump is a variable-geometry structure designed to reduce the drag induced by shock wave ensure wing’s aerodynamic performance over the entire range of operating conditions. To meet this target, the SMA bump requires to exhibit two-way shape memory effect (TWSME) so that it can yield continuous shape change by properly changing the driving temperature. Result from differential scanning calorimetry was first presented to provide material’s phase transformation temperatures. To obtain the TWSME, a thermo-mechanical training procedure was proposed and a set of training devices were designed for training SMA bump. The SMA bump in this paper is trained to have a relatively flat shape in high temperature and can swell up when cooling. After more than 80 times training, the TWSME of the material tends to be stable. Then the thermo-mechanical responses of the SMA bump which is subjected to about 100 times training was tested. The result shows that the trained SMA bump can generate about 1.2 mm maximum recoverable deformation during martensitic transformation, which is about 3% of the ratio of the deformation region. Finally, the influence of external load on the thermo-mechanical response of the trained SMA bump were also studied.

Structure and mobility of martensite variant interfaces in a Cu-Zn-AI shape memory alloy

2003 ◽  
Vol 112 ◽  
pp. 519-522 ◽  
Author(s):  
W. Cai ◽  
J. X. Zhang ◽  
Y. F. Zheng ◽  
L. C. Zhao
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Martensite Variant
Sign in / Sign up

Export Citation Format

Share Document