定向凝固Cu-Pb偏晶合金摩擦磨损性能的研究

Study on Friction and Wear Performance of Directionally Solidified Cu-Pb Monotectic Alloy

通过定向凝固制备了Cu-Pb偏晶合金试样,并分别进行了无润滑和油润滑条件下的摩擦磨损实验。结果表明:干摩擦条件下定向凝固Cu-Pb金属基自润滑复合材料的摩擦系数随铅含量的增加而下降,减摩自润滑效果逐渐提高。铜铅自润滑材料在含油的状态下,形成了一种复合润滑体制,具有很强的吸油能力,能形成高效能的胶体油铅混合液态薄膜。由于摩擦接触表面间油膜的存在,减轻了微凸凹体的接触及表面间元素传递过程,降低了摩擦系数。由于定向凝固工艺方法使得第二相更加均匀,因此该方法制备的铜铅自润滑材料普遍比熔铸方法制备的铜铅自润滑材料在油润滑状态下的摩擦系数要低。

The Cu-Pb monotectic alloys were prepared by the directional solidification, and the friction and wear tests of directionally solidified Cu-Pb alloys were performed under dry sliding condition and oil lubrication. The results show that, under the dry sliding condition, the friction coefficient of directionally solidified Cu-Pb alloy becomes small and the anti-attrition improves with the increase of the lead content. Under the oil lubrication, the mixed film is formed between the bearing and journal surface. Mass transfer becomes weak between the sample and grinding disc. The friction coefficient becomes small due to the existence of the film. In the mean time, the friction coefficient of the sample prepared by the directional solidification is smaller than that of the sample prepared by the conventional casting, because the distribution of second liquid droplets in the sample prepared by the directional solidification is more homogenous than that of the sample prepared by the conventional casting.