滚压诱导纯铜表面梯度纳米结构磨损行为研究

Study on Wear Behavior of Gradient Nanocrystalline Structure on Pure Copper Surface Induced by Burnishing

使用自主设计的高效平面滚压刀具对纯铜进行表面制造,利用塑性变形诱导在纯铜表面制备梯度纳米结构;采用金相显微镜、透射电子显微镜等对梯度纳米结构进行表征,量化变形强化层厚度,考察晶粒尺寸分布;对梯度纳米结构的磨损行为进行研究,并解释了相关机理。结果表明,滚压诱导后表层纳米晶粒细化小于20 nm,并随深度逐渐增至基体晶粒尺寸,形成了十分明显的梯度结构,同时具有较为理想的表面粗糙度和截面硬度分布;干摩擦试验表明,低载时梯度纳米结构具有较好抗粘着能力,摩擦性能较好;高载时由于表层纳米结构强烈变形,微碎裂及随后的三体磨损反而降低了摩擦性能。

Surface manufacturing of pure copper is conducted by a novel surface burnishing tool. Gradient nanocrystalline structure is prepared on pure copper surface based on plastic deformation. Said gradient nanocrystalline structure is characterized by metallographic microscope and transmission electron microscope. Thickness of gradient nanocrystalline structure and diameter of nanocrystalline are measured, respectively. Wear behavior of gradient nanocrystalline structure is also investigated. Results show the diameters of nanocrystalline are less than 20 nm. There is obvious gradient nanocrystalline structure on copper surface after burnishing. The surface roughness and cross-sectional hardness distribution after burnishing are also ideal. Results of dry friction experiments show that when the load is low, the gradient nanocrystalline structure exhibit advantage in resisting adhesion, so friction performance is better. When the load is high, the gradient nanocrystalline structure is destroyed by severe plastic deformation. Subsequently, micro fracture and the following three-body wear decrease the friction performance of gradient nanocrystalline structure.