W-20Cu复合材料高温高速摩擦磨损行为及机理研究

发布时间：2018-03-15 01:27

  本文选题：高温　切入点：高速　出处：《河南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：钨铜复合材料因其高硬度、高强度、导热导电性好等优良性能被用作电磁炮导轨材料及高压开关触头材料。在实际使用过程中,材料常常处于热、力、电多场耦合的严酷工况下,服役条件下材料的力学性能及微观组织演变直接关系到零件的使用寿命和服役安全性。以往研究集中在钨铜材料的制备和导电等性能上,而对于钨铜材料的摩擦磨损行为鲜有关注,基于此,本文选用W-20Cu复合材料分别与45钢和7075Al进行配副,系统研究了高温、高速干摩擦条件下钨铜复合材料及配副材料的摩擦磨损行为、机理及组织演变。本文首先分析了高速条件下,不同退火态钨铜材料摩擦磨损性能及其行为。结果发现,在750~950℃温度范围内,当保温时间为1 h时,随着退火温度的升高,钨铜复合材料的导电率、硬度和密度变化趋势相同,均先升高再下降。当退火温度分别为800℃和900℃时,随着保温时间的延长,硬度先升高后降低,导电率降低。800℃×0.5 h时导电率达到峰值,为47.32%IACS。900℃×1 h时硬度达到峰值,为285 HB。退火处理后W-20Cu/45钢摩擦系数以及钨铜材料的磨损率与处理前相比均有所降低。W-20Cu/45钢硬度差值在60~90 HB时,摩擦系数较低,最低值为0.09。不同退火态W-20Cu/45钢磨损机制为氧化磨损和粘着磨损。在温度50~300℃内,选择W-20Cu复合材料与45钢对磨,随环境温度的升高,摩擦系数先升高再下降,温度超过200℃钨铜材料磨损率剧烈上升。分析表明,速度100 r/min时,W-20Cu/45钢磨损机制主要为磨粒磨损和氧化磨损。当速度超过100 r/min时,W-20Cu/45钢磨损机制主要为疲劳磨损、磨粒磨损和氧化磨损。在室温环境下,载荷400~800 N范围内,随着载荷升高,对磨盘45钢磨损率变化不大,钨铜材料磨损率剧烈上升,产生大量片状磨屑。W-20Cu/45钢摩擦系数随着载荷的升高而升高。在重载条件下,W-20Cu/45钢磨损机制为磨粒磨损、剥落磨损为主,粘着磨损为辅。高速滑块式摩擦磨损试验摩擦速度为26~57 m/s,试验结果表明,在高速环境下,W-20Cu/45钢磨损机制和W-20Cu/7075Al磨损机制均为粘着磨损和磨粒磨损。随着摩擦速度增加,W-20Cu/45钢和W-20Cu/7075Al的摩擦系数均是随着滑动速度的升高而降低,钨铜材料的磨损率随滑动的速度增高而降低。
[Abstract]:Tungsten and copper composites are used as materials for electromagnetic gun rails and high voltage switch contacts because of their high hardness, high strength and good thermal conductivity. The mechanical properties and microstructure evolution of materials in service are directly related to the service life and safety of parts under the harsh condition of electric-multi-field coupling. Previous studies focused on the preparation and conductive properties of tungsten and copper materials. However, little attention has been paid to the friction and wear behavior of tungsten and copper materials. Based on this, W-20Cu composite was used to match with 45 steel and 7075Al respectively, and the high temperature was studied systematically. The friction and wear behavior, mechanism and microstructure evolution of tungsten and copper composites and matching materials under high speed and dry friction conditions are analyzed in this paper. The friction and wear properties and behaviors of different annealed tungsten copper materials at high speed are analyzed. In the range of 750 ~ 950 鈩，

本文编号：1613834