Tang Mingkai, Zhang Lichao, Shi Yusheng, Zhu Wenzhi, Zhang Nan
School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoshi Road, Wuhan 430074, China.
Materials (Basel). 2019 Feb 20;12(4):630. doi: 10.3390/ma12040630.
During various applications in aerospace, ships, autos, and aircraft, 7075 Al alloy will frequently contact other materials, and therefore suffer from slight abrasion. However, the poor tribological properties of 7075 Al alloy greatly affect its performance and life length, leading to limitations in its application. Preparing roughness structures on the surface is regarded as a promising method to improve the properties of materials. However, the tribological properties of 7075 Al alloy cannot be enhanced significantly by roughness structures in complex dynamic changeable environments, owing to the incomplete understanding of the effect of roughness structures. Given the above issues, in this paper, micro-scale structures (linear grooves, gridding grooves, and arc grooves) were designed and prepared on 7075 Al alloy surfaces by a surface treatment (laser micro-engraving), which provides excellent controllability of the morphology and dimensions of as-prepared roughness structures. The tribological properties of the as-prepared surfaces were investigated systemically. The effect of micro-scale structures on the tribological properties was studied. The wear mechanism and tribological properties improvement mechanism of the surfaces were clarified. Furthermore, the effect degree of the enhancement factors of the micro-scale structures on the tribological properties was explored under different conditions. The results indicate that the micro-scale structures play an important role in improving the tribological properties of Al alloy under different sliding speeds. The improvement mechanism can be summarized by four factors. However, the effect degrees of these factors on the tribological properties exhibit considerable differences. This study not only develops specific micro-scale structures that can dramatically improve the tribological properties of 7075 Al alloy under different conditions, but also offers guidance for the construction of appropriate roughness structures that can dramatically improve the tribological properties of Al alloy according to the friction conditions.
在航空航天、船舶、汽车和飞机等各种应用中，7075铝合金经常会与其他材料接触，因此会遭受轻微磨损。然而，7075铝合金较差的摩擦学性能极大地影响了其性能和使用寿命，导致其应用受到限制。在材料表面制备粗糙度结构被认为是改善材料性能的一种很有前景的方法。然而，由于对粗糙度结构的影响理解不全面，在复杂动态变化的环境中，粗糙度结构并不能显著提高7075铝合金的摩擦学性能。针对上述问题，本文通过表面处理（激光微刻蚀）在7075铝合金表面设计并制备了微尺度结构（线性槽、网格槽和弧形槽），这为所制备的粗糙度结构的形貌和尺寸提供了出色的可控性。系统地研究了所制备表面的摩擦学性能。研究了微尺度结构对摩擦学性能的影响。阐明了表面的磨损机制和摩擦学性能改善机制。此外，还探索了不同条件下微尺度结构增强因子对摩擦学性能的影响程度。结果表明，微尺度结构在不同滑动速度下对改善铝合金的摩擦学性能起着重要作用。改善机制可归纳为四个因素。然而，这些因素对摩擦学性能的影响程度存在显著差异。本研究不仅开发了在不同条件下能显著改善7075铝合金摩擦学性能的特定微尺度结构，还为根据摩擦条件构建能显著改善铝合金摩擦学性能的合适粗糙度结构提供了指导。
