陈弦教授在超弹性块状合金材料中实现了数百万周期的疲劳寿命
由机械及航空航天工程学系副教授陈弦领导的研究小组，近日在力学和材料科学领域上取得了突破。在理论指导下，他们研发了一种具有出色变形能力丶且不会发生应变硬化的合金，即使经过了一千万次拉伸应力诱发相变，仍能保持其变形可逆性。
这项工作深入探索应力诱发马氏体相变的微观结构和相容性条件。当材料的微观结构满足孪晶相容性条件，在拉应力作用下，材料的超弹性寿命达到数百万次。类似的相变材料可以被广泛地应用在各个领域，如支架丶生物医学植入物丶微执行器和固态冷却装置等。
他们的研究在着名物理学期刊《物理评论快报》上发表，标题为「Nondissipative Martensitic Phase Transformation after Multimillion Superelastic Cycles」。在论文中，他们揭示了经数百万机械循环，应力诱发相变呈现出零内耗，结构性和功能性疲劳几乎消失。通过高分辨透射电子显微镜的研究，他们揭示了零内耗马氏体相变的本质：即材料的晶格常量满足「余因子条件－超相容条件」。
通过阐释这零内耗相变背後的机制，陈弦教授的团队显着提高了形状记忆合金材料的疲劳寿命，为这种材料的先进设计开辟了新方向，并进一步扩大材料於医疗设备及能源科学上的应用。这项突破为开发可承受数百万次周期疲劳寿命的创新材料带来了新希望，从而提高了这些材料於各项关键应用的性能和可靠性。
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The Hong Kong University of Science and Technology (HKUST) (https://hkust.edu.hk/) is a world-class research intensive university that focuses on science, technology and business as well as humanities and social science. HKUST offers an international campus, and a holistic and interdisciplinary pedagogy to nurture well-rounded graduates with global vision, a strong entrepreneurial spirit and innovative thinking. Over 80% of our research work were rated “Internationally excellent” or “world leading” in the Research Assessment Exercise 2020 of Hong Kong’s University Grants Committee. We were ranked 3rd in Times Higher Education’s Young University Rankings 2022, and our graduates were ranked 23rd worldwide and among the best from universities from Asia in Global Employability University Ranking and Survey 2021.
