Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals

In this research, thermomechanical behavior and thermally induced fracture of single crystal Ni-Mn-Ga FSMAs were investigated. Results show that 1. Ni-Mn-Ga FSMAs exhibited two way memory effect during thermal cycling; however, the stability is very sensitive to the temperature rate and external loa...

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Main Author: Xiong, Feng
Other Authors: Liu Yong
Format: Theses and Dissertations
Published: 2008
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Online Access:https://hdl.handle.net/10356/5425
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-54252023-03-11T18:07:16Z Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals Xiong, Feng Liu Yong School of Mechanical and Aerospace Engineering DRNTU::Engineering::Materials::Metallic materials::Alloys In this research, thermomechanical behavior and thermally induced fracture of single crystal Ni-Mn-Ga FSMAs were investigated. Results show that 1. Ni-Mn-Ga FSMAs exhibited two way memory effect during thermal cycling; however, the stability is very sensitive to the temperature rate and external load. 2. The crack propagation behavior is strongly related to the forward transformation and the martensitic twin structure. Thermomechanical fatigue cracks in Ni-Mn-Ga FSMAs prefer to propagate along the twin boundaries as well as twin-twin intersections through multiple propagation modes. 3. Theoretical analysis on the thermally induced fracture behavior of Ni-Mn-Ga FSMA shows that the primary reason for the thermally induced fracture in Ni-Mn-Ga FSMAs is the increase in the crack tip stress intensity factor (SIF) due to stress redistribution around the crack tip as a result of stress-induced martensitic (SIM) transformation. With lowering the temperature to approach to the martensite start temperature, the crack tip SIF of Ni-Mn-Ga FSMA increases significantly, which is responsible for its brittleness under thermal cycling and is strongly related to the yield stress, temperature dependence of the critical stress for SIM transformation and transformation interval. DOCTOR OF PHILOSOPHY (MAE) 2008-09-17T10:50:14Z 2008-09-17T10:50:14Z 2008 2008 Thesis Xiong, F. (2008). Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/5425 10.32657/10356/5425 Nanyang Technological University application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
topic DRNTU::Engineering::Materials::Metallic materials::Alloys
spellingShingle DRNTU::Engineering::Materials::Metallic materials::Alloys
Xiong, Feng
Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals
description In this research, thermomechanical behavior and thermally induced fracture of single crystal Ni-Mn-Ga FSMAs were investigated. Results show that 1. Ni-Mn-Ga FSMAs exhibited two way memory effect during thermal cycling; however, the stability is very sensitive to the temperature rate and external load. 2. The crack propagation behavior is strongly related to the forward transformation and the martensitic twin structure. Thermomechanical fatigue cracks in Ni-Mn-Ga FSMAs prefer to propagate along the twin boundaries as well as twin-twin intersections through multiple propagation modes. 3. Theoretical analysis on the thermally induced fracture behavior of Ni-Mn-Ga FSMA shows that the primary reason for the thermally induced fracture in Ni-Mn-Ga FSMAs is the increase in the crack tip stress intensity factor (SIF) due to stress redistribution around the crack tip as a result of stress-induced martensitic (SIM) transformation. With lowering the temperature to approach to the martensite start temperature, the crack tip SIF of Ni-Mn-Ga FSMA increases significantly, which is responsible for its brittleness under thermal cycling and is strongly related to the yield stress, temperature dependence of the critical stress for SIM transformation and transformation interval.
author2 Liu Yong
author_facet Liu Yong
Xiong, Feng
format Theses and Dissertations
author Xiong, Feng
author_sort Xiong, Feng
title Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals
title_short Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals
title_full Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals
title_fullStr Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals
title_full_unstemmed Thermally induced fracture and thermomechanical properties of NI-MN-GA-FSMA single crystals
title_sort thermally induced fracture and thermomechanical properties of ni-mn-ga-fsma single crystals
publishDate 2008
url https://hdl.handle.net/10356/5425
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