Ti50Ni15Pd25Cu10與Ti48.9Ni49.1Fe2形狀記憶合金箔帶之麻田散體相變態行為與機械性質之研究

Research on Martensitic Transformation Behaviors and Mechanical Properties of Ti50Ni15Pd25Cu10 and Ti48.9Ni49.1Fe2 Shape Memory Alloy Ribbons

蘇唯仁(Wei-Jen Su)

指導教授 ： 陳志軒

國立臺灣大學/工學院/機械工程學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202202037

摘要

本研究利用快速凝固製程(RSP)製備Ti50Ni15Pd25Cu10 與Ti48.9Ni49.1Fe2形狀記憶合金箔帶，並針對其麻田散體相變態行為、微結構、形狀記憶效應、超彈性以及彈熱效應進行探討。本研究結果顯示，400°C、500°C的時效條件會對於Ti48.9Ni49.1Fe2箔帶的相變態溫度有提升的效果，說明熱處理對於Ti48.9Ni49.1Fe2箔帶基地成分以及顯微結構產生影響，並影響其機械性質，但對於熱循環穩定性的影響並不顯著，因為B2相與R相間的晶格相容性很好，本來就有良好的熱循環穩定性。結果也顯示出，400°C、500°C的時效條件會使Ti50Ni15Pd25Cu10箔帶長出Ti2Pd析出物，對基地成分造成影響，進而使相變態溫度降低，結果也顯示Ti50Ni15Pd25Cu10箔帶經過時效後產生Ti2Pd析出物隊熱循環穩定性有提升的效果。研究發現箔帶因為製程而具有厚度不均的問題，造成應變分布不均，進而影響其機械性質，為了使箔帶機械性質獲得改善，對箔帶嘗試利用冷加工方式來改善厚度均勻性，比較冷加工前後箔帶之形狀記憶特性以及機械性質。結果顯示，箔帶經過冷加工後其厚度的均勻度獲得提升，使應變在箔帶各處較為均勻，並可以進一步的提升其各項功能性表現，包含形狀記憶效應、超彈性以及彈熱性能。

關鍵字

形狀記憶合金箔帶 ； 冷加工 ； 形狀記憶效應 ； 超彈性 ； 彈熱效應

並列摘要

This study investigated the phase transformation behavior, microstructure, shape memory effect, superelasticity, and elastocaloric effect of Ti50Ni15Pd25Cu10 and Ti48.9Ni49.1Fe2 shape memory ribbons, which were fabricated by rapid solidification process (RSP). Experimental results showed that the aging conditions of 400 °C and 500 °C increased the phase transformation temperatures of Ti48.9Ni49.1Fe2 ribbon, indicating that heat treatment had an impact on the matrix composition and microstructure of Ti48.9Ni49.1Fe2 ribbon, which in turn affected the mechanical properties. Besides, the effect of aging treatment on thermal cycling stability was not significant for the Ti48.9Ni49.1Fe2 ribbon due to the interfacial compatability was already excellent for the B2 to R-phase trasnformation. For the Ti50Ni15Pd25Cu10 ribbon, the aging conditions of 400 °C and 500 °C reduced the phase transformation temperatures due to the formation of Ti2Pd precipitates. Furthermore, the thermal cycle stability was improved by the formation of Ti2Pd. It was found that the thickness of the ribbons was uneven due to the RSP process, resulting in uneven strain distribution, which in turn affected its mechanical properties. In order to improve the mechanical properties of the ribbons, cold rolling was applied to improve the thickness homogeneity. The cold-rolled ribbons showed better shape memory characteristics due to less stress concentration, and thus the martensitic transformation was more uniform throughout the ribbon. With the additional cold-rolling process, the functional performance of shape memory ribbons, including shape memory effect, superelasticity, and elastocaloric effect, could be further improved.

並列關鍵字

shape memory ribbon ； cold roll ； shape memory effect ； superelasticity ； elastocaloric effect

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