纳米孪晶超硬材料的高压合成

发布时间：2018-06-06 14:06

本文选题：超硬材料 + 霍尔-佩奇效应　；参考：《物理学报》2017年03期

【摘要】：超硬材料研究有两个重要难题一直备受关注:一是建立晶体宏观性能硬度与微观电子结构参数的定量关联,指导新型超硬晶体的设计;二是发现改进超硬材料综合性能(硬度、韧性和稳定性)的基本原理和技术途径,合成出综合性能更加优异的高性能超硬材料.首先从同时联系晶体硬度和电子结构的化学键出发,提出了共价晶体的压痕硬度为晶体中化学键对压头压入过程的综合阻抗的基本假设,建立了共价晶体硬度的微观模型并推广至多晶共价材料.在多晶硬度模型指导下,在高温高压条件下成功地合成出了纳米孪晶结构的立方氮化硼和金刚石块材,实现了硬度、韧性及热稳定性这三大工具材料性能指标的同时提高.另外,澄清了关于压痕硬度测量的长期争论.本文的研究为研发高性能超硬材料打开了一条新的技术途径,有望带来机械加工业和高压科学领域的新变革.
[Abstract]:There are two important problems in the study of superhard materials: one is to establish the quantitative correlation between the microstructural parameters and the hardness of the crystal macroscopical properties to guide the design of the new superhard crystals, and the other is to find the improvement of the comprehensive properties of the superhard materials (hardness, hardness). Based on the basic principles and technical approaches of toughness and stability, high performance superhard materials with better comprehensive properties have been synthesized. Starting from the combination of the hardness of the crystal and the chemical bond of the electronic structure, the basic assumption that the indentation hardness of the covalent crystal is the comprehensive impedance of the chemical bond to the indenter process in the crystal is proposed. The micromodel of covalent crystal hardness was established and extended to polycrystalline covalent materials. Under the guidance of polycrystalline hardness model, cubic boron nitride (CBN) and diamond blocks with nanocrystalline structure were successfully synthesized under high temperature and high pressure. The properties of three tool materials, hardness, toughness and thermal stability, were improved at the same time. In addition, the long-term controversy about indentation hardness measurement is clarified. The research in this paper opens up a new technical approach for the research and development of high performance superhard materials, and it is expected to bring new changes in the field of mechanical processing and high pressure science.
【作者单位】：燕山大学亚稳材料制备技术与科学国家重点实验室;
【基金】：国家自然科学基金(批准号:51525205,51421091,51332005) 河北省杰出青年基金(批准号:E2014203150)资助的课题~~
【分类号】：TQ163;O521.9

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