Hinkle Adam R, Nöhring Wolfram G, Leute Richard, Junge Till, Pastewka Lars
Material, Physical and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, NM 87123, USA.
Institute for Applied Materials, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
Sci Adv. 2020 Feb 14;6(7):eaax0847. doi: 10.1126/sciadv.aax0847. eCollection 2020 Feb.
Most natural and man-made surfaces appear to be rough on many length scales. There is presently no unifying theory of the origin of roughness or the self-affine nature of surface topography. One likely contributor to the formation of roughness is deformation, which underlies many processes that shape surfaces such as machining, fracture, and wear. Using molecular dynamics, we simulate the biaxial compression of single-crystal Au, the high-entropy alloy NiCoFeTi, and amorphous CuZr and show that even surfaces of homogeneous materials develop a self-affine structure. By characterizing subsurface deformation, we connect the self-affinity of the surface to the spatial correlation of deformation events occurring within the bulk and present scaling relations for the evolution of roughness with strain. These results open routes toward interpreting and engineering roughness profiles.
大多数天然和人造表面在许多长度尺度上看起来都是粗糙的。目前还没有关于粗糙度起源或表面形貌自仿射性质的统一理论。粗糙度形成的一个可能因素是变形，它是许多塑造表面的过程（如加工、断裂和磨损）的基础。我们使用分子动力学模拟了单晶金、高熵合金镍钴铁钛和非晶态铜锆的双轴压缩，结果表明，即使是均质材料的表面也会形成自仿射结构。通过表征亚表面变形，我们将表面的自仿射性与体相中发生的变形事件的空间相关性联系起来，并给出了粗糙度随应变演变的标度关系。这些结果为解释和设计粗糙度轮廓开辟了道路。
