Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation
In this study, the effect of the addition of Hf on the oxidation behavior of NiTi alloy, which was processed using additive manufacturing and casting, is studied. Thermogravimetric analyses (TGA) were performed at the temperature of 500, 800, and 900 °C to assess the isothermal and dynamic oxidation...
Main Authors: | , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2020-05-01
|
Series: | Materials |
Subjects: | |
Online Access: | https://www.mdpi.com/1996-1944/13/9/2104 |
id |
doaj-74be469c12f341b4873d2880ae22d84b |
---|---|
record_format |
Article |
spelling |
doaj-74be469c12f341b4873d2880ae22d84b2020-11-25T02:19:37ZengMDPI AGMaterials1996-19442020-05-01132104210410.3390/ma13092104Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature OxidationHediyeh Dabbaghi0Keyvan Safaei1Mohammadreza Nematollahi2Parisa Bayati3Mohammad Elahinia4Department of Mechanical, Industrial, and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606, USADepartment of Mechanical, Industrial, and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606, USADepartment of Mechanical, Industrial, and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606, USADepartment of Mechanical, Industrial, and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606, USADepartment of Mechanical, Industrial, and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606, USAIn this study, the effect of the addition of Hf on the oxidation behavior of NiTi alloy, which was processed using additive manufacturing and casting, is studied. Thermogravimetric analyses (TGA) were performed at the temperature of 500, 800, and 900 °C to assess the isothermal and dynamic oxidation behavior of the Ni50.4Ti29.6Hf20 at.% alloys for 75 h in dry air. After oxidation, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to analyze the oxide scale formed on the surface of the samples during the high-temperature oxidation. Two stages of oxidation were observed for the NiTiHf samples, an increasing oxidation rate during the early stage of oxidation followed by a lower oxidation rate after approximately 10 h. The isothermal oxidation curves were well matched with a logarithmic rate law in the initial stage and then by parabolic rate law for the next stage. The formation of multi-layered oxide was observed for NiTiHf, which consists of Ti oxide, Hf oxide, and NiTiO<sub>3</sub>. For the binary alloys, results show that by increasing the temperature, the oxidation rate increased significantly and fitted with parabolic rate law. Activation energy of 175.25 kJ/mol for additively manufactured (AM) NiTi and 60.634 kJ/mol for AM NiTiHf was obtained.https://www.mdpi.com/1996-1944/13/9/2104additive manufacturinghigh-temperature shape memory alloysoxidationNiTiHfNiTi |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Hediyeh Dabbaghi Keyvan Safaei Mohammadreza Nematollahi Parisa Bayati Mohammad Elahinia |
spellingShingle |
Hediyeh Dabbaghi Keyvan Safaei Mohammadreza Nematollahi Parisa Bayati Mohammad Elahinia Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation Materials additive manufacturing high-temperature shape memory alloys oxidation NiTiHf NiTi |
author_facet |
Hediyeh Dabbaghi Keyvan Safaei Mohammadreza Nematollahi Parisa Bayati Mohammad Elahinia |
author_sort |
Hediyeh Dabbaghi |
title |
Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation |
title_short |
Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation |
title_full |
Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation |
title_fullStr |
Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation |
title_full_unstemmed |
Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation |
title_sort |
additively manufactured niti and nitihf alloys: estimating service life in high-temperature oxidation |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2020-05-01 |
description |
In this study, the effect of the addition of Hf on the oxidation behavior of NiTi alloy, which was processed using additive manufacturing and casting, is studied. Thermogravimetric analyses (TGA) were performed at the temperature of 500, 800, and 900 °C to assess the isothermal and dynamic oxidation behavior of the Ni50.4Ti29.6Hf20 at.% alloys for 75 h in dry air. After oxidation, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to analyze the oxide scale formed on the surface of the samples during the high-temperature oxidation. Two stages of oxidation were observed for the NiTiHf samples, an increasing oxidation rate during the early stage of oxidation followed by a lower oxidation rate after approximately 10 h. The isothermal oxidation curves were well matched with a logarithmic rate law in the initial stage and then by parabolic rate law for the next stage. The formation of multi-layered oxide was observed for NiTiHf, which consists of Ti oxide, Hf oxide, and NiTiO<sub>3</sub>. For the binary alloys, results show that by increasing the temperature, the oxidation rate increased significantly and fitted with parabolic rate law. Activation energy of 175.25 kJ/mol for additively manufactured (AM) NiTi and 60.634 kJ/mol for AM NiTiHf was obtained. |
topic |
additive manufacturing high-temperature shape memory alloys oxidation NiTiHf NiTi |
url |
https://www.mdpi.com/1996-1944/13/9/2104 |
work_keys_str_mv |
AT hediyehdabbaghi additivelymanufacturednitiandnitihfalloysestimatingservicelifeinhightemperatureoxidation AT keyvansafaei additivelymanufacturednitiandnitihfalloysestimatingservicelifeinhightemperatureoxidation AT mohammadrezanematollahi additivelymanufacturednitiandnitihfalloysestimatingservicelifeinhightemperatureoxidation AT parisabayati additivelymanufacturednitiandnitihfalloysestimatingservicelifeinhightemperatureoxidation AT mohammadelahinia additivelymanufacturednitiandnitihfalloysestimatingservicelifeinhightemperatureoxidation |
_version_ |
1724875486649122816 |