ISSN   1004-0595

CN  62-1224/O4

高级检索

2A70铝合金高温切向微动摩擦磨损特性研究

High-Temperature Tangential Fretting Wear Behaviour of 2A70 Aluminum Alloy

  • 摘要: 高温作为影响离心叶轮服役寿命的关键因素,本文中选择离心叶轮材料2A70铝合金作为研究对象,探究了不同温度(25、100、175和 250 ℃)下2A70铝合金微动摩擦磨损特性,主要对完全滑移区(50 μm)磨痕的微观形貌、摩擦学化学状态与磨损机制进行探讨. 结果表明:在相同的载荷位移条件下,温度的上升并未使微动运行界面的运行状态改变,但对摩擦系数、摩擦耗散能及磨损机制有着显著影响. 在高温工况下,2A70铝合金的材料磨损程度高于室温工况,其磨损机制为磨粒磨损、黏着磨损和氧化磨损. 随着温度的升高,摩擦系数和磨损体积先增大后减小,当温度达到100和175 ℃时,材料受高温热软化影响导致其抗变形能力降低,微动磨损加剧;当温度达到250 ℃时,氧化磨屑层能在较低的循环次数下形成并减少摩擦副之间接触面积,在一定程度上降低了材料磨损.

     

    Abstract: High temperature is a key factor affecting the service life of centrifugal impellers. In this paper, 2A70 aluminum alloy, a centrifugal impeller material was selected as the research object, and the fretting wear characteristics of 2A70 aluminum alloy at different temperatures (25, 100, 175, 250 ℃) were studied. The micro-morphology, tribological chemical state and main damage mechanism of the fretting wear in the slip regime (50 μm) were mainly discussed. The result demonstrated that in the same load and displacement conditions, the fretting regime was not modified by raising the temperature, but it had a significant influence on the friction coefficient, frictional dissipation energy and fretting wear mechanism. In the high temperature conditions, the material damage degree of 2A70 aluminum alloy was higher than that in the room temperature, the fretting wear mechanism included abrasive wear, adhesive wear and oxidative wear. With temperature increasing, the friction coefficient and wear volume ascended at first and then descended with increasing temperature. When the temperatures reached 100 and 175 ℃, due to the influence of high temperature thermal softening, the deformation resistance of the material was reduced and the fretting damage was intensified. When the temperature reached 250 ℃, the oxide debris layer could form at a lower number of cycles, reducing the contact area between friction pair and alleviating the material abrasion.

     

/

返回文章
返回