Transient heat transfer and heat storage effect in thermoelastic martensitic transformation

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K04981
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26010:Metallic material properties-related
• Research Institution: Hokkaido University
• Principal Investigator: KATO HIROYUKI 北海道大学, 工学研究院, 准教授 (80224533)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 相変態 / 形状記憶合金 / 伝熱工学 / アクチュエータ

Outline of Final Research Achievements

Shape memory effect occurs by raising the temperature of shape memory material after deformation. The original shape can be recovered after the heating. The heating process requires additional heat energy to that of the heat capacity. The amount of additional heat is the latent heat or the heat of sublimation. We know that the latent heat for melting ice is used for ice packs and ice pillows. The latent heat of shape memory alloy can be used to cool down the temperature of electronic devices without the accident of water leak. In order to develop engineering application of the latent heat of shape memory alloys, present study has examined the amount of heat and the heat transfer effect. In particular, it is found that the latent heat of Nickel Titanium alloy, which is known for the medical use in blood vessels stent, is largest among various shape memory alloys. The alloy is a promising candidate for the latent heat storage material.

Free Research Field

材料力学

Academic Significance and Societal Importance of the Research Achievements

形状記憶合金の熱弾性型マルテンサイト変態について、潜熱の絶対値およびその非定常伝達について検討し，固体蓄熱材料の応用を提案した。文献では，様々な形状記憶合金の中でニッケルチタン合金の潜熱が最も大きく，今回，実験により文献値よりも大きい±36J/gの値を得た。潜熱の発生は試料温度の局所的な乱れを伴い、その乱れを二次元温度分布の熱画像として初めて撮影した。形状記憶合金で液漏れのない固体の冷却材を創るための基礎的な物性を明らかにするとともに，モデルによる視覚的な実証を行った。