双尺度结构Al-Sn合金的自组织摩擦层形成规律和摩擦学性能研究

进一步提高纳米相合金的摩擦学性能，关键在于解决磨痕亚表层中合金塑形变形不稳定性和自润滑相减少等问题，本质上是改善合金自组织摩擦层的结构与性能。本项目根据摩擦非线性特征和材料塑性变形机制，提出宏观上强韧化合金基体和微观上调控亚表层结构演变的协同改性新思路：一方面拟采用机械合金化法制备出双尺度复合结构Al-12wt%Sn合金，通过“硬-软”双区的协同变形改善磨痕亚表层的塑性变形机制，提高合金自组织摩擦层的稳定性；另一方面拟通过改变Sn相尺度、剪切应变和添加异质Si相等方法调控磨痕亚表层中自润滑Sn相的自组织反应，提高游离态Sn相在自组织摩擦层中的富集和扩散。二者协同作用，在双尺度结构Al-Sn合金的磨痕表面、亚表层共同构筑具有高稳定性和润滑性的自组织摩擦层，是同步提高纳米相复合结构Al-Sn合金耐磨性和减摩性的有效方法。本项研究提供了一种全新的发展双相合金高摩擦学性能的思路和方法。

For further improve tribological properties of nanocomposite alloy，the key is to solve both the plastic deformation instability of nanocomposite alloy and the reduction of self-lubricating phase in worn subsurface, and to promote the structures and properties of self-organized tribolayer substantially. According to the non-linear character of friction and plastic deformation of materials, this project provides a synergetic combination of toughened high-strength macroscopic matrix and control subsurface microstructural evolution. On the one hand, a dual-scale structured Al-12wt%Sn alloy will be produced by mechanical alloying, and a stabilized self-organized tribolayer will be formed in the worn subsurface due to that the improvement of plastic deformation mechanism of Al-Sn alloy is produced by the synergetic deformation mechanism of the matching of “had-soft” phases. On the other hand, in order to increase the enrichment and diffusion of free form Sn phase in the worn subsurface, some methods such as changing Sn size and shear strain, adding Si will be used to control the self-organization reaction of self-lubricating Sn phase. A synergetic work happens between the two aspects, a self-organized tribolayer combining high stabilization and lubrication will be formed in the worn surface and subsurface of the dual-scale Al-Sn alloy, it also provides an effective method to further improve the wear and friction performance of nanocomposite Al-Sn alloy synchronously. The research results demonstrate a bran-new idea and method to develop high wear performance for the dual-phase alloy.