磨损表面形貌的影响
(中南大学 粉末冶金国家重点实验室, 长沙 410083)
摘 要: 以炭纤维针刺整体毡为预制体，经化学气相渗透和树脂浸渍增密方式得到C/C复合材料。采用有限元分析软件，模拟飞机在正常着陆条件下，刹车盘在制动过程中的热应力分布，并研究热应力对C/C复合材料磨损表面形貌的影响。结果表明：热应力是由于摩擦热的不均匀分布引起的。在摩擦表面外径处温度较高，产生的热应力较大，最大值约为3.15 MPa；而在靠近内径处温度较低，热应力较小，约为1.78 MPa。内、外径处热应力的差异导致磨损表面具有两种不同的组织形貌；靠近外径处的磨损表面比较粗糙，摩擦膜不完整，颜色暗淡，为“暗带”的组织形貌，摩擦性能较差；而靠近内径处的磨损表面光滑，摩擦膜连续稳定，颜色明亮，为“亮带”的组织形貌，摩擦性能较好。
关键字: C/C复合材料；有限元；热应力；磨损表面
C/C composites during braking
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The thermal stress field of C/C composites with needled carbon fiber perform densified by chemical vapor infiltration and impregnating resin was simulated by finite element method in simulating normal landing. And the effect of thermal stress on the worn surface morphology was investigated. The results show that the thermal stress is caused by the existence of the non-uniform frictional heat on the contact surface. The temperature and thermal stress near the outer diameter of the friction surface are higher than those near the inner diameter. The maximum thermal stress near the outer diameter is 3.15 MPa and the thermal stress near the inner diameter is 1.78 MPa. Two different worn surface appearances can be observed on the sample because of the thermal stress distribution. The higher thermal stress near the outer diameter induces the rough and dull surface morphology named ‘dark band’, which has worse friction property. While the thermal stress near the inner diameter is lower, the surface is smooth and allows the maintenance of uniform and bright friction film named ‘bright band’, which has better friction property.
Key words: C/C composites; finite element; thermal stress; worn surface
