Study on Friction and Wear Characteristics of Advanced Al Alloy Matrix Composites

以铝硅合金浸渍石墨复合材料(Al-Gr)销与轴承钢盘为接触对象，在恒定接触载荷条件下，以空气相对湿度(RH)为变量，在离子交换水中进行了单向滑动摩擦磨损试验，研究了Al-Gr复合材料作为先进滑动材料的摩擦磨损特性。主要考察了大气中氧气和水蒸气的影响。在中等RH范围内，复合材料的摩擦磨损最小，这是因为在圆盘滑动表面形成了由铝合金磨屑和石墨粉组成的致密膜，防止了金属与金属之间的粘结。研究了氧化铝短纤维增强铝硅合金基复合材料(AFRMMC)与铝合金(JIS AC8A或A2017)在润滑油中的摩擦磨损特性。在一定负荷下，AFRMMC相对于A2017在机械油和发动机基础油中的摩擦系数(μ)迅速增加。然而，虽然摩擦模式转变为边界润滑，但未出现μ快速增加的载荷水平。此外，以空气中的相对滑移幅度为变量，研究了Al-Gr和AFRMMC与轴承钢接触时的微动特性。在测试的整个相对滑移幅度范围内，Al-Gr具有良好的微动摩擦学性能。

Unidirectional sliding friction and wear tests of an Al-Si alloy impregnated graphite composite (Al-Gr) pin in contact with a bearing steel disk were conducted at a constant contact load as a variable of relative humidity (RH) in air and argon gas, and in ion-exchanged water, aimed at investigating friction and wear characteristics of the composite expected as an advanced sliding material. The influence of oxygen and water vapor in the atmosphere were mainly investigated. The composite has a minimum in friction and wear in the middle RH range, since compacted films consisting of Al alloy wear debris and graphite powders are zonally formed on the disk sliding surface, preventing adhesion due to metal-to-metal contact.Friction and wear characteristics of an alumina short fiber-reinforced Al-Si alloy matrix composite (AFRMMC) in contact with Al alloy (JIS AC8A or A2017) were elucidated in lubricating oil. Friction coefficient (μ) rapidly increases at a certain load for the AFRMMC against A2017 in machine oil and engine base oil. However, the load level where μ rapidly increases for the AFRMMC against AC8A does not appear, although the frictional mode transits to the boundary lubrication.Fretting characteristics of the Al-Gr and AFRMMC in contact with bearing steel were also investigated from test results in air as a variable of relative slip amplitude. The Al-Gr exhibited good tribological performance during fretting over the whole range of relative slip amplitude tested.