Coherency strains of H-phase precipitates and their influence on functional properties of nickel-titanium-hafnium shape memory alloys

2018 ◽  
Vol 147 ◽  
pp. 83-87 ◽  
Author(s):  
Behnam Amin-Ahmadi ◽  
Joseph G. Pauza ◽  
Ali Shamimi ◽  
Tom W. Duerig ◽  
Ronald D. Noebe ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Functional Properties ◽  
Nickel Titanium ◽  
Coherency Strains

The electron beam freeform fabrication of NiTi shape memory alloys. Part I: Microstructure and physical–chemical behavior

2020 ◽  
pp. 146442072097505
Author(s):  
RPM Guimarães ◽  
F Pixner ◽  
G Trimmel ◽  
J Hobisch ◽  
T Rath ◽  
...  
Keyword(s):  
Electron Beam ◽  
Additive Manufacturing ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Freeform Fabrication ◽  
Austenitic Transformation ◽  
Columnar Grains ◽  
One Step ◽  
Niti Shape Memory Alloys

Nickel–titanium alloys are the most widely used shape memory alloys due to their outstanding shape memory effect and superelasticity. Additive manufacturing has recently emerged in the fabrication of shape memory alloy but despite substantial advances in powder-based techniques, less attention has been focused on wire-based additive manufacturing. This work reports on the preliminary results for the process-related microstructural and phase transformation changes of Ni-rich nickel–titanium alloy additively manufactured by wire-based electron beam freeform fabrication. To study the feasibility of the process, a simple 10-layer stack structure was successfully built and characterized, exhibiting columnar grains and achieving one-step reversible martensitic–austenitic transformation, thus showing the potential of this additive manufacturing technique for processing shape memory alloys.

A Comparative Study of Structure Formation in Thermomechanically Treated Ti-Ni and Ti-Nb-(Zr, Ta) SMA

2012 ◽  
Vol 706-709 ◽  
pp. 1931-1936 ◽  
Author(s):  
Sergey Prokoshkin ◽  
Vladimir Brailovski ◽  
Karine Inaekyan ◽  
Andrey Korotitskiy ◽  
Sergey Dubinskiy ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Comparative Study ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Structure Formation ◽  
Thermomechanical Treatment ◽  
Functional Properties ◽  
Nanocrystalline Structure ◽  
Technological Factors

The processes of structure formation in Ti-Ni and in Ti-Nb-Zr, Ti-Nb-Ta shape memory alloys (SMA) under thermomechanical treatment (TMT) were studied. The TMT comprised cold rolling with true strains from e=0.25 to 2 and post-deformation annealing. Differences in these processes between two groups of alloys are considered. The main conclusions are as follows: nanostructures created by TMT are useful for radical improvement of the SMA functional properties, and an optimum nanostructure (nanocrystalline structure, nanosubgrained structure or theirmixture) should be selected by taking into account other structural and technological factors.

scholarly journals Crystallographic Attributes of a Shape-Memory Alloy

1999 ◽  
Vol 121 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Kaushik Bhattacharya
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Potential Applications

Shape-memory Alloys are attractive for many potential applications. In an attempt to provide ideas and guidelines for the development of new shape-memory alloys, this paper reports on a series of investigations that examine the reasons in the crystallography that make (i) shape-memory alloys special amongst martensites and (ii) Nickel-Titanium special among shape-memory alloys.

Creation of submicrocrystalline structure and improvement of functional properties of shape memory alloys of the Ti-Ni-Fe system with the help of ECAP

2007 ◽  
Vol 49 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
S. D. Prokoshkin ◽  
M. N. Belousov ◽  
V. Ya. Abramov ◽  
A. V. Korotitskii ◽  
S. Yu. Makushev ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Functional Properties ◽  
Submicrocrystalline Structure

Mechanics of nickel–titanium shape memory alloys undergoing partially constrained recovery for self-healing materials

2018 ◽  
Vol 29 (15) ◽  
pp. 3025-3036 ◽  
Author(s):  
Nathan Salowitz ◽  
Ameralys Correa ◽  
Trishika Santebennur ◽  
Afsaneh Dorri Moghadam ◽  
Xiaojun Yan ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Self Healing ◽  
Bonding Agents ◽  
Compressive Loads ◽  
Martensitic State ◽  
Geometric Changes ◽  
Shape Memory Fibers

Engineered self-healing materials seek to create an innate ability for materials to restore mechanical strength after incurring damage, much like biological organisms. This technology will enable the design of structures that can withstand their everyday use without damage but also recover from damage due to an overload incident. One of the primary mechanisms for self-healing is the incorporation of shape memory fibers in a composite type structure. Upon activation, these shape memory fibers can restore geometric changes caused by damage and close fractures. To date, shape memory–based self-healing, without bonding agents, has been limited to geometric restoration without creating a capability to withstand externally applied tensile loads due to the way the shape memory material has been integrated into the composite. Some form of bonding has been necessary for self-healing materials to resist an externally applied load after healing. This article presents results of new study into using a form of constrained recovery of nickel–titanium shape memory alloys in self-healing materials to create residual compressive loads across fractures in the low temperature martensitic state. Analysis is presented relating internal loads in self-healing materials, potentially generated by shape memory alloys, to the capability to resist externally applied loads. Supporting properties were experimentally characterized in nickel–titanium shape memory alloy wires. Finally, self-healing samples were synthesized and tested demonstrating the ability to resist externally applies loads without bonding. This study provides a new useful characterization of nickel–titanium applicable to self-healing structures and opens the door to new forms of healing like incorporation of pressure-based bonding.

Creep behavior of Nickel–Titanium shape-memory alloys under static and dynamic loadings: an FEM approach

2021 ◽  
Vol 136 (1) ◽  
Author(s):  
Saad Fariduddin Shaikh ◽  
Subrata Kumar Panda ◽  
Nitin Sharma ◽  
Shreeshan Jena
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Creep Behavior ◽  
Nickel Titanium ◽  
Dynamic Loadings

Effect of the quasi-continuous equal-channel angular pressing on the structure and functional properties of Ti–Ni-based shape-memory alloys

2017 ◽  
Vol 118 (3) ◽  
pp. 279-287 ◽  
Author(s):  
I. Yu. Khmelevskaya ◽  
R. D. Karelin ◽  
S. D. Prokoshkin ◽  
V. A. Andreev ◽  
V. S. Yusupov ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Equal Channel Angular Pressing ◽  
Functional Properties ◽  
Angular Pressing
Sign in / Sign up

Export Citation Format

Share Document