Next Article in Journal
An Investigation into Creep Cavity Development in 316H Stainless Steel
Previous Article in Journal
Review of Aluminum-To-Steel Welding Technologies for Car-Body Applications
Previous Article in Special Issue
Ab Initio Study of the Combined Effects of Alloying Elements and H on Grain Boundary Cohesion in Ferritic Steels
Article Menu
Issue 3 (March) cover image

Export Article

Open AccessArticle
Metals 2019, 9(3), 316; https://doi.org/10.3390/met9030316

Hydrogen Effect on the Cyclic Behavior of a Superelastic NiTi Archwire

1
Laboratory of Mechanics of Sousse, National Engineering School of Sousse, University of Sousse, Sousse 4054, Tunisia
2
Department of Mechanical Engineering, College of Engineering, King Khalid University, Abha 61421, Saudi Arabia
3
Laboratory of Electromechanical Systems (LASEM), National Engineering School of Sfax, University of Sfax, Route de Soukra km 4, Sfax 3038, Tunisia
4
Research Center for Advanced Materials Science (RCAMS), King Khalid University, PO Box 9004, Abha 61413, Asir, Saudi Arabia
*
Author to whom correspondence should be addressed.
Received: 13 February 2019 / Revised: 4 March 2019 / Accepted: 7 March 2019 / Published: 11 March 2019
Full-Text   |   PDF [3174 KB, uploaded 12 March 2019]   |  

Abstract

In this work, we are interested in examining the strain rate effect on the mechanical behavior of Ni–Ti superelastic wires after hydrogen charging and ageing for 24 h. Specimens underwent 50 cycles of loading-unloading, reaching an imposed deformation of 7.6%. During loading, strain rates from 10−4 s−1 to 10−2 s−1 were achieved. With a strain rate of 10−2 s−1, the specimens were charged by hydrogen for 6 h and aged for one day showed a superelastic behavior marked by an increase in the residual deformation as a function of the number of cycles. In contrast, after a few number of cycles with a strain rate of 10−4 s−1, the Ni-Ti alloy archwire specimens fractured in a brittle manner during the martensite transformation stage. The thermal desorption analysis showed that, for immersed specimens, the desorption peak of hydrogen appeared at 320 °C. However, after annealing the charged specimens by hydrogen at 400 °C for 1 h, an embrittlement took place at the last cycles for the lower strain rates of 10−4 s−1. The present study suggests that the embrittlement can be due to the development of an internal stress in the subsurface of the parent phase during hydrogen charging and due to the creation of cracks and local zones of plasticity after desorption. View Full-Text
Keywords: hydrogen; NiTi alloys; superelastic; martensite; cyclic effect hydrogen; NiTi alloys; superelastic; martensite; cyclic effect
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Sarraj, R.; Kessentini, A.; Hassine, T.; Algahtani, A.; Gamaoun, F. Hydrogen Effect on the Cyclic Behavior of a Superelastic NiTi Archwire. Metals 2019, 9, 316.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Metals EISSN 2075-4701 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top