陳弦教授在超彈性塊狀合金材料中實現了數百萬周期的疲勞壽命
由機械及航空航天工程學系副教授陳弦領導的研究小組,近日在力學和材料科學領域上取得了突破。在理論指導下,他們研發了一種具有出色變形能力、且不會發生應變硬化的合金,即使經過了一千萬次拉伸應力誘發相變,仍能保持其變形可逆性。
這項工作深入探索應力誘發馬氏體相變的微觀結構和相容性條件。當材料的微觀結構滿足孿晶相容性條件,在拉應力作用下,材料的超彈性壽命達到數百萬次。類似的相變材料可以被廣泛地應用在各個領域,如支架、生物醫學植入物、微執行器和固態冷卻裝置等。
他們的研究在著名物理學期刊《物理評論快報》上發表,標題為「Nondissipative Martensitic Phase Transformation after Multimillion Superelastic Cycles」。在論文中,他們揭示了經數百萬機械循環,應力誘發相變呈現出零內耗,結構性和功能性疲勞幾乎消失。通過高分辨透射電子顯微鏡的研究,他們揭示了零內耗馬氏體相變的本質:即材料的晶格常量滿足「餘因子條件-超相容條件」。
通過闡釋這零內耗相變背後的機制,陳弦教授的團隊顯著提高了形狀記憶合金材料的疲勞壽命,為這種材料的先進設計開闢了新方向,並進一步擴大材料於醫療設備及能源科學上的應用。這項突破為開發可承受數百萬次周期疲勞壽命的創新材料帶來了新希望,從而提高了這些材料於各項關鍵應用的性能和可靠性。
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