Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Effect of Cu Content and Annealing Temperature on the Shape Memory Effect of NiTi-based Alloy

구리함량과 어닐링 온도가 NiTi 합금의 형상기억효과에 미치는 영향

  • Hyeok-Jin Yang (School of Materials Science and Engineering, Kumoh National Institute of Technology) ;
  • Hyeong Ju Mun (School of Materials Science and Engineering, Kumoh National Institute of Technology) ;
  • Ye-Seul Cho (School of Materials Science and Engineering, Kumoh National Institute of Technology) ;
  • Jun-Hong Park (School of Materials Science and Engineering, Kumoh National Institute of Technology) ;
  • Hyun-Jun Youn (School of Materials Science and Engineering, Kumoh National Institute of Technology) ;
  • In-Chul Choi (School of Materials Science and Engineering, Kumoh National Institute of Technology) ;
  • Myung-Hoon Oh (School of Materials Science and Engineering, Kumoh National Institute of Technology)
  • 양혁진 (금오공과대학교 신소재공학부) ;
  • 문형주 (금오공과대학교 신소재공학부) ;
  • 조예슬 (금오공과대학교 신소재공학부) ;
  • 박준홍 (금오공과대학교 신소재공학부) ;
  • 윤현준 (금오공과대학교 신소재공학부) ;
  • 최인철 (금오공과대학교 신소재공학부) ;
  • 오명훈 (금오공과대학교 신소재공학부)
  • Received : 2024.03.07
  • Accepted : 2024.03.19
  • Published : 2024.03.30
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Abstract

The effects of annealing heat treatment and the addition of Cu element on the shape memory effect of the NiTi-based alloy were investigated by analyzing differential scanning calorimeter results and characterizing recovery rate through 3D scanning after Vickers hardness test. Through 3D scanning of impressions after Vickers hardness test, the strain recovery rates for specimens without annealing treatment and annealed specimens at 400, 450, and 500℃ were measured as 45.96%, 46.76%, 52.37%, and 43.57%, respectively. This is because as the annealing temperature increases, both B19' and NiTi2 phases, which can impede martensitic transformation, are incorporated within the NiTi matrix. Particularly, additional phase transformation from R-phase to B19' observed in specimens annealed at 400 and 450℃ significantly contributes to the improvement in strain recovery rates. Additionally, the results regarding the Cu element content indicate that when the total content of Ni and Cu is below 49.6 at.%, the precipitation of fine B19' and NiTi2 phases within the matrix can greatly influence the transformation enthalpy and temperature range, resulting in relatively lower strain recovery rates in NiTi alloys with a small amount of Cu element produced in this study.

Keywords

Acknowledgement

이 연구는 금오공과대학교 대학 학술연구비로 지원되었습니다(2022년도).

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