Interface integrity based on the control of strain-induced anisotropic diffusion

采用分子动力学方法分析了ni基高温合金在高温单轴应变作用下的降解机理。应变诱导的各向异性扩散使垂直于界面的Al原子之间精细分散。（Ni3Al）相和。在Ni(001)/Ni3Al（001）界面结构中清晰地观察到相（Ni基体）。发现Al、Co、Cu、W和Ti原子加速了漂流过程。另一方面，发现Ta、Pd、Zr、Mo和Mg原子抑制了漂流。利用薄膜叠层结构进行了实验验证。0。采用四点弯曲法对叠层结构进行退火时，在平行界面处施加2%的拉伸应变。结果表明，垂直于界面方向的原子扩散速度大大加快。同时证实，合金中已掺杂的钛和钨原子严重加速了这一现象。另一方面，钯和钽的加入可以有效地抑制界面周围Al原子的扩散。因此，将MD分析应用于新型耐热材料的设计，对于提高下一代能源发电厂的效率是非常有效的。

The degradation mechanism of Ni-base superalloy under an uni-axial strain at high temperature was analyzed by molecular dynamics (MD)analysis. The strain-induced anisotropic diffusion of Al atoms perpendicular to the interface between finely dispersed .' (Ni3Al)phase and . phase (Ni matrix)was observed clearly in a Ni(001)/Ni3Al(001)interface structure. It was found that Al, Co, Cu, W, and Ti atoms accelerated the rafting. On the other hand, Ta, Pd, Zr, Mo, and Mg atoms were found to suppress the rafting. The estimated results were validated by experiments using thin-film stacked structures. The 0. 2%tensile strain was applied parallel to the interface during the annealing of the stacked structure by using a four-point bending method. It was confirmed that the diffusion of atoms perpendicular to the interface was accelerated drastically. It was also confirmed that titanium and tungsten atoms which are already doped in the alloy accelerated this phenomenon seriously. On the other hand, the addition of palladium and tantalum was found to be effective for suppressing the diffusion of Al atoms around the interface. Therefore, the application of MD analysis to the design of a novel heat resistant material is very effective for improving the efficiency of energy power plants for next generation.