OPTIMIZATION OF SHAPE MEMORY EFFECT IN FE-BASED SHAPE MEMORY ALLOYS BY MODIFICATION OF SOLUTION TREATMENT TEMPERATURE | ||
| The International Conference on Applied Mechanics and Mechanical Engineering | ||
| Article 28, Volume 18, 18th International Conference on Applied Mechanics and Mechanical Engineering., April 2018, Pages 1-9 PDF (7.64 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/amme.2018.34964 | ||
| Authors | ||
| M. K. El Fawkhry1, 2; V. Sampath3; T. Mattar4 | ||
| 1Central Metallurgical and Research and Development Institute (CMRDI), Cairo, Egypt.+ | ||
| 2corresponding author. | ||
| 3Department of Metallurgical and Materials Engineering, Indian Institute of | ||
| 4Central Metallurgical and Research and Development Institute (CMRDI), Cairo, Egypt. | ||
| Abstract | ||
| ABSTRACT Solution treatment is an important process parameter in the context of thermo mechanical processing of shape memory alloys. It is one of the preliminary steps that is required to obtain martensite in the alloys. As far as martensite is concerned, it forms the basis of shape memory effect as shape memory alloys are used capitalizing on their unique properties of shape memory effect and superelastic effect. It is well known that the grain size of austenite in the solutionized condition depends on the austenitizing/solutionizing temperature. Moreover, the solution treatment temperature influences the transformation temperatures of SMAS. It has been found by researchers that solutionizing temperature brings about modification in the grain size, the grain boundary angles, and the annealing twins. The major objective of the present work is to assess the influence of modifications in the microstructural features brought about increasing/decreasing the solution treatment temperature. Optical microscopic and back scattered electron diffraction studies reveal the microstructural changes brought about by changing the solutionizing temperature. The X-ray diffraction experiments reveal the increase in SIEM in the alloy that was solution treated at 800, 900, 1000°C. The TEM studies reveal the formation of stacking faults and their interaction with one another and also with the grain boundaries. The results indicate that solutionizing at an optimal temperature of 1000°C leads to increased shape recovery strain as well as shape recovery stress. The results are presented and discussed in the paper. | ||
| Keywords | ||
| shape memory alloy; Iron based shape memory alloy; Solution treatment; Shape memory effect; Stress recovery | ||
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