CrAlN硬质刀具涂层的相结构稳定性及其热分解机制

发布时间：2018-04-09 23:36

本文选题：CrAlN　切入点：硬质刀具涂层　出处：《中国有色金属学报》2016年01期

【摘要】：采用基于密度泛函理论的第一性原理计算方法,从理论上系统研究不同Al固溶浓度x(x=0~1)下面心立方(FCC)结构Cr1-xAlxN硬质刀具涂层的微观几何构型、相结构稳定性及其热分解机制,并从电子结构角度对其稳定性起源进行分析。结果表明:随着Al固溶浓度增大,FCC-Cr1-xAlxN晶胞逐渐收缩,而其晶格畸变程度却先增大后减小,且当Al浓度x为0.5~0.75时,FCC-Cr1-xAlxN晶格畸变较为严重,为析出密排六方(HCP)结构的Al N化合物提供源动力;随着Al固溶浓度增大,FCC-Cr1-xAlxN相结构稳定性逐渐降低,且其极易按FCC-Cr1-xAlxN→(FCC-Cr N)+(HCP-Al N)→(HCP-Cr2N)+N2+(HCP-Al N)的路径进行分解,计算结果与实验保持一致;Al固溶致使FCC-Cr1-xAlxN相结构稳定性降低的内在原因在于Cr1-xAlxN晶胞中Cr—N共价键作用随Al固溶度的增大而逐渐减弱。
[Abstract]:Based on density functional theory (DFT), the microcosmic geometry, phase stability and thermal decomposition mechanism of Cr1-xAlxN hard tool coatings with different Al solid solution concentrations (xX) / FCC1) are systematically studied by using the first principle method based on density functional theory (DFT), and the results are as follows: (1) the microcosmic geometry, phase stability and thermal decomposition mechanism of Cr1-xAlxN hard tool coatings with different Al solid solution concentrations are systematically studied.The origin of its stability is analyzed from the point of view of electronic structure.The results show that the lattice distortion of FCC-Cr1-xAlxN cell shrinks gradually with the increase of Al solution concentration, but the lattice distortion degree increases first and then decreases, and the lattice distortion of FCC-Cr1-xAlxN is more serious when Al concentration x is 0.5 ~ 0.75, and the lattice distortion of FCC-Cr1-xAlxN is more serious than that of FCC-Cr1-xAlxN.The internal reason that the stability of FCC-Cr1-xAlxN phase decreases due to the solution of Al is consistent with the experimental results is that the covalent bond interaction of Cr-N in Cr1-xAlxN cell decreases with the increase of Al solubility.
【作者单位】：长沙理工大学工程车辆轻量化与可靠性技术湖南省高校重点实验室;长沙理工大学工程车辆安全性设计与可靠性技术湖南省重点实验室;湖南大学材料与科学工程学院;
【基金】：国家自然科学基金资助项目(51401036) 湖南省自然科学基金资助项目(14JJ3086)~~
【分类号】：TG711

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