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纳米结构超硬材料的机遇与挑战

Opportunities and challenges for nanostructured superhard materials

  • 摘要: 经过几十年的研究和发展,纳米结构金刚石和立方氮化硼已相继被成功制备,其高硬度和强韧性充分表明纳米力学增强机制是制备超强超硬材料的有效途径。目前纳米结构超硬材料的研究仍处于起步阶段,高温高压相转变的路径与机制、复杂中间相的结构与产生的条件、热力学条件对晶粒生长和微结构(孪晶和堆垛层错等)形成的作用,以及超硬材料的纳米结构对力学性能和强化机制的影响等尚未完全揭示出来。为此,文章对近年来在相关领域的研究进行综述,总结了设计与寻找超硬材料的一般策略与原则,概括了典型的纳米微结构对超硬材料力学与热稳定性的影响,归纳了纳米结构超硬材料的高温高压相变与转化机制,并对当前的研究进展和潜在应用进行了归纳与展望。

     

    Abstract: Over decades of research and development, nanostructured diamond and cubic boron nitride have been successfully synthesized, and their high hardness and strength fully demonstrate that their nanomechanical enhancement mechanism is an effective way to pre‐ pare superstrong and superhard materials. To date, knowledge of such nanostructured superhard materials is still limited, and there are many mysteries surrounding the effects of pressure and temperature on the grain growth and defect formation (e. g., twins and stacking faults) during the synthesis. Moreover, the nanoeffects on the mechanical properties and the related underlying strengthening mechanisms of nanostructured superhard materials are still under debate. We review the research in related fields in recent years, outline the strategies and principles for designing and finding superhard materials, and describe the influence of typical nanostructures on the mechanical and thermal stability of these materials. The high-temperature and highpressure phase transitions and transformation mechanisms are discussed, and current research progress as well as potential applications are summarized.

     

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