Microstructure and Hardness of Copper Based Shape Memory Alloys with Fourth Alloying Elements

Authors

  • Wee Ying Ci School of Mechanical Engineering, Faculty of Engineering Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor
  • Muhammad Hafiz Akhbar School of Mechanical Engineering, Faculty of Engineering Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor
  • Tuty Asma Abu Bakar School of Mechanical Engineering, Faculty of Engineering Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor

Keywords:

Shape memory alloys, Cu based shape memory alloys, fourth alloying elements, microstructure, hardness

Abstract

Many potential applications of Cu based shape memory alloys (SMAs) are restricted due to the brittleness of the material. This research was conducted to enhance the mechanical properties of the Cu based SMAs. The research examined the effects of adding the fourth alloying elements, i.e., Boron (B), Cobalt (Co) and Titanium (Ti) on the microstructures and mechanical properties of the Cu based SMAs. The fabrication of Cu-Al-Ni alloys with these fourth alloying elements was carried out using a casting method. Several characterization tests were conducted to identify the effects of the fourth alloying elements using Scanning Electron Microscope (SEM), Optical Microscope, and Vickers hardness test. From the microstructural observation, it was found that the grain sizes of these alloys were refined with the addition of the fourth alloying elements. The addition of B shows the most fined grain size. The SEM results indicate that the microstructures consisted of two types of martensite, which were ð›½1with an 18R structure, and ð›¾1 with a 2H structure. The ð›¾1, looking like parallel martensite morphologies, are known as lamella structures. This type of lamella morphologies has also grown into grain. The ð›½1 phase is typically formed with self accommodating groups in two different morphologies, plates and needles. The precipitation existed in the structure known as ð›¾2, which also existed and acted like barriers in the grain boundaries. ð›¾2 precipitates can be found in grain boundaries and in between structure ð›½1 and ð›¾1. The addition of the fourth alloying elements shows an increment in the hardness of the alloys in which the addition of Ti element demonstrates the highest hardness value.

References

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Published

2019-05-14

How to Cite

Ying Ci, W., Akhbar, M. H., & Abu Bakar, T. A. (2019). Microstructure and Hardness of Copper Based Shape Memory Alloys with Fourth Alloying Elements. Jurnal Mekanikal, 41(2). Retrieved from https://jurnalmekanikal.utm.my/index.php/jurnalmekanikal/article/view/331

Issue

Section

Mechanical

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