Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , 72 Wenhua Road , Shenyang 110016 , China.
Institute for Applied Materials (IAM) , Karlsruhe Institute of Technology (KIT) , 12 Kaiserstrasse , Karlsruhe 76131 , Germany.
ACS Appl Mater Interfaces. 2018 Apr 25;10(16):13829-13838. doi: 10.1021/acsami.8b01205. Epub 2018 Apr 10.
A gradient nano-grained (GNG) surface layer is fabricated on a commercial-purity Cu sample, in which a significant reduction in the coefficient of friction and the wear loss is obtained compared to the coarse-grained and the nano-grained counterparts. A novel mild ploughing mechanism without subsurface damage has been identified in the GNG sample, giving rise to a much reduced wear rate. Sliding induced surface deformation brings about the unique inhomogeneous substructure in the GNG Cu: the topmost layer persists with nanograins without being oxidized, underneath which deformation is well accommodated by grain coarsening adjacent to the dynamic recrystallization layer. Both subsurface structural evolution and stress field model confirm that sliding-induced strain localization is suppressed, which is responsible for the superior friction and wear behaviors of the GNG Cu.
在商业纯铜样品上制备了梯度纳米晶（GNG）表面层，与粗晶和纳米晶相比，其摩擦系数和磨损损失显著降低。在 GNG 样品中发现了一种新颖的无亚表面损伤的温和犁耕机制，从而使磨损率大大降低。滑动引起的表面变形导致 GNG Cu 具有独特的非均匀亚结构：最顶层保持纳米晶粒而不被氧化，在其下，通过与动态再结晶层相邻的晶粒粗化来很好地适应变形。亚表面结构演化和应力场模型都证实，滑动引起的应变局部化受到抑制，这是 GNG Cu 具有优异摩擦和磨损性能的原因。
