Influence of pre-strain on the strain rate response of Ni-Ti shape memory alloy / Nur Aliah Mohd Khairi...[et al.]

Mohd Khairi, Nur Aliah and Ibrahim, Azmi and Ab Hamid, Hanizah (2019) Influence of pre-strain on the strain rate response of Ni-Ti shape memory alloy / Nur Aliah Mohd Khairi...[et al.]. Journal of Mechanical Engineering (JMechE), 16 (2). pp. 157-166. ISSN 1823-5514 ; 2550-164X


The presence of Shape Memory Alloy (SMA) in civil engineering fields offered a lot of advantages to the industries. The superiority of SMA is when the material has the ability to remember its previous shape after it has deformed and it will return back to its original defined shape when it is subjected to heat. Nickel-Titanium (Ni-Ti) is known as the finest alloy among SMA groups. In this research, the influence of pre-strain on the mechanical behavior of Ni-Ti shape memory alloy bars were examined in room temperature with concerns of a different strain rates, which are 5.5x10-4 s-1 and 1x10-3 s-1. Each of the test piece was pre-strained at level 5ξ, 10ξ and 15ξ. A quasi-static tensile test was carried out on heat treated Ni-Ti by using a Universal Testing Machine to observe the Ni-Ti stress-strain response. The results show tensile strength of Ni-Ti increased after applying pre-strain and heat treatment at 500°C. However, it is observed tensile strength of Ni-Ti started to drop after pre-strained at 15ξ. So, it indicates that strain ageing of Ni-Ti bars at a large strain becomes practically irrelevant, even though Ni-Ti is a super-alloy. Furthermore, Ni-Ti is a strain rate dependent material where the strength increases at a higher rate. Thus, it was found Ni-Ti exhibited yield strength differently where the yield strength increases as the strain rate decreases.


Item Type: Article
Email / ID Num.
Mohd Khairi, Nur Aliah
Ibrahim, Azmi
Ab Hamid, Hanizah
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: Universiti Teknologi MARA, Shah Alam > Faculty of Mechanical Engineering
Journal or Publication Title: Journal of Mechanical Engineering (JMechE)
UiTM Journal Collections: UiTM Journal > Journal of Mechanical Engineering (JMechE)
ISSN: 1823-5514 ; 2550-164X
Volume: 16
Number: 2
Page Range: pp. 157-166
Keywords: Ni-Ti, Shape memory alloy, Pre-strain, Strain rate, Tensile
Date: 2019
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