纳米尺度圆孔表面薄膜界面失配位错形核机理

MISFIT DISLOCATIONS IN AN ANNULAR STRAINED FILM GROWN ON A CYLINDRICAL NANOPORE SURFACE WITH INTERFACE STRESS

  • 摘要: 研究了无限大基体内纳米尺度圆孔表面薄膜中界面螺型位错形核的临界条件,薄膜考虑了表/界面效应。运用弹性复势方法,获得了两个区域应力场的解析解答,并导出位错形核能公式,由此讨论了表/界面效应对薄膜界面位错形核的影响规律。算例结果表明,表/界面效应在纳米尺度下对位错形核的影响显著,不同表/界面效应下位错形核的临界薄膜厚度有很大差异,当基体与薄膜的相对剪切模量超过某一值后,只有考虑负的表/界面应力时位错才有可能形核;薄膜厚度在小于某一临界尺寸时负的表/界面应力更容易位错形核,薄膜厚度大于某一临界尺寸时正的表/界面应力更容易位错形核。

     

    Abstract: The critical formation condition of screw misfit dislocation which locates in a cylindrical nanopore surface with interface stress is investigated. The analytical solutions of complex potential functions in the film and the infinite matrix are derived by means of the complex variable method, with the aid of complex potential functions. The elastic energy of the misfit dislocation is given, which revels the influence of the surface/interface effects on the formation of misfit dislocation which grows on a cylindrical nanopore surface. The results show that surface/interface effects on the nanoscale have great effect on misfit dislocation formation, and the critical formation condition of screw misfit dislocation can have large differences with different surface/interface effects in the critical film thickness. When the composite substrate and film of the relative shear modulus exceeds a certain value, screw misfit dislocation can form only considering negative surface/interface effects. Misfit dislocation forms easier when considering the negative surface/interface effects in smaller film thickness. A larger film thickness is found more prone to form misfit dislocation under the surface/interface effects.

     

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