Li Zhuohan, Szlufarska Izabela
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706-1595, USA.
Phys Rev Lett. 2021 Feb 19;126(7):076001. doi: 10.1103/PhysRevLett.126.076001.
We used density functional theory calculations to investigate the physical origin of the mechanochemical response of material interfaces. Our results show that the mechanochemical response can be decomposed into the contribution from the interface itself (deformation of interfacial bonds) and a contribution from the underlying solid. The relative contributions depend on the stiffness of these regions and the contact geometry, which affects the stress distribution within the bulk region. We demonstrate that, contrary to what is commonly assumed, the contribution to the activation volume from the elastic deformation of the surrounding bulk is significant and, in some case, may be dominant. We also show that the activation volume and the mechanochemical response of interfaces should be finite due to the effects on the stiffness and stress distribution within the near-surface bulk region. Our results indicate that the large range of activation volumes measured in the previous experiments even for the same material system might originate from the different degrees of contributions probed from the bulk vs interface.
我们使用密度泛函理论计算来研究材料界面机械化学响应的物理起源。我们的结果表明，机械化学响应可以分解为来自界面本身的贡献（界面键的变形）和来自下层固体的贡献。相对贡献取决于这些区域的刚度和接触几何形状，这会影响块状区域内的应力分布。我们证明，与通常的假设相反，周围块状材料弹性变形对活化体积的贡献是显著的，在某些情况下可能占主导地位。我们还表明，由于对近表面块状区域内刚度和应力分布的影响，界面的活化体积和机械化学响应应该是有限的。我们的结果表明，即使对于相同的材料系统，先前实验中测得的大范围活化体积可能源于从块状材料与界面探测到的不同程度的贡献。
