Effects of heat treatment on the shape recovery of selective-laser melted NiTi

The complexity in conventionally manufacturing NiTi has led to the additive manufacturing of NiTi with Selective Laser Melting (SLM). Considering the importance of the shape memory properties in Nitinol, it is therefore essential to investigate ways to improve it in SLM printed NiTi samples. In the...

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Main Author: Lee, Dennis Ying Le
Other Authors: Liu Erjia
Format: Final Year Project
Language:English
Published: 2018
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Online Access:http://hdl.handle.net/10356/75625
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-756252023-03-04T18:45:05Z Effects of heat treatment on the shape recovery of selective-laser melted NiTi Lee, Dennis Ying Le Liu Erjia Liu Yong School of Mechanical and Aerospace Engineering DRNTU::Engineering::Materials::Metallic materials::Alloys The complexity in conventionally manufacturing NiTi has led to the additive manufacturing of NiTi with Selective Laser Melting (SLM). Considering the importance of the shape memory properties in Nitinol, it is therefore essential to investigate ways to improve it in SLM printed NiTi samples. In the project, the NiTi samples were produced by melting NiTi powder (50.16 .at% Ni, 49.84 .at% Ti) using SLM. The samples were subjected to rapid annealing for 5 minutes at different heat treatment temperatures: 400 ⁰C, 500 ⁰C, 600 ⁰C and 700 ⁰C. It was observed that the sample heat treated at 400 ⁰C showed the greatest transformation strain and shape recovery. The ASTM Grain Size Number was also observed to decrease with increasing annealing temperature. Differential Scanning Calorimetry (DSC) was used to determine the phase transformation temperatures for the NiTi samples. The DSC curves showed two peaks in proximity for both the cooling and heating cycles, suggesting the absence of the intermediate R-phase. The two peaks in the DSC curves were attributed to the two-step SLM process and it was concluded that cooling time for affects the extent of solidification for SLM NiTi. Energy-Dispersive X-ray Spectroscopy and X-Ray Diffraction confirmed the existence of the Ti2Ni precipitates in the NiTi samples. Bachelor of Engineering (Aerospace Engineering) 2018-06-05T08:30:42Z 2018-06-05T08:30:42Z 2018 Final Year Project (FYP) http://hdl.handle.net/10356/75625 en Nanyang Technological University 70 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Materials::Metallic materials::Alloys
spellingShingle DRNTU::Engineering::Materials::Metallic materials::Alloys
Lee, Dennis Ying Le
Effects of heat treatment on the shape recovery of selective-laser melted NiTi
description The complexity in conventionally manufacturing NiTi has led to the additive manufacturing of NiTi with Selective Laser Melting (SLM). Considering the importance of the shape memory properties in Nitinol, it is therefore essential to investigate ways to improve it in SLM printed NiTi samples. In the project, the NiTi samples were produced by melting NiTi powder (50.16 .at% Ni, 49.84 .at% Ti) using SLM. The samples were subjected to rapid annealing for 5 minutes at different heat treatment temperatures: 400 ⁰C, 500 ⁰C, 600 ⁰C and 700 ⁰C. It was observed that the sample heat treated at 400 ⁰C showed the greatest transformation strain and shape recovery. The ASTM Grain Size Number was also observed to decrease with increasing annealing temperature. Differential Scanning Calorimetry (DSC) was used to determine the phase transformation temperatures for the NiTi samples. The DSC curves showed two peaks in proximity for both the cooling and heating cycles, suggesting the absence of the intermediate R-phase. The two peaks in the DSC curves were attributed to the two-step SLM process and it was concluded that cooling time for affects the extent of solidification for SLM NiTi. Energy-Dispersive X-ray Spectroscopy and X-Ray Diffraction confirmed the existence of the Ti2Ni precipitates in the NiTi samples.
author2 Liu Erjia
author_facet Liu Erjia
Lee, Dennis Ying Le
format Final Year Project
author Lee, Dennis Ying Le
author_sort Lee, Dennis Ying Le
title Effects of heat treatment on the shape recovery of selective-laser melted NiTi
title_short Effects of heat treatment on the shape recovery of selective-laser melted NiTi
title_full Effects of heat treatment on the shape recovery of selective-laser melted NiTi
title_fullStr Effects of heat treatment on the shape recovery of selective-laser melted NiTi
title_full_unstemmed Effects of heat treatment on the shape recovery of selective-laser melted NiTi
title_sort effects of heat treatment on the shape recovery of selective-laser melted niti
publishDate 2018
url http://hdl.handle.net/10356/75625
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