磨損表面形貌的影響
(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室, 長(zhǎng)沙 410083)
摘 要: 以炭纖維針刺整體氈為預(yù)制體，經(jīng)化學(xué)氣相滲透和樹(shù)脂浸漬增密方式得到C/C復(fù)合材料。采用有限元分析軟件，模擬飛機(jī)在正常著陸條件下，剎車(chē)盤(pán)在制動(dòng)過(guò)程中的熱應(yīng)力分布，并研究熱應(yīng)力對(duì)C/C復(fù)合材料磨損表面形貌的影響。結(jié)果表明：熱應(yīng)力是由于摩擦熱的不均勻分布引起的。在摩擦表面外徑處溫度較高，產(chǎn)生的熱應(yīng)力較大，最大值約為3.15 MPa；而在靠近內(nèi)徑處溫度較低，熱應(yīng)力較小，約為1.78 MPa。內(nèi)、外徑處熱應(yīng)力的差異導(dǎo)致磨損表面具有兩種不同的組織形貌；靠近外徑處的磨損表面比較粗糙，摩擦膜不完整，顏色暗淡，為“暗帶”的組織形貌，摩擦性能較差；而靠近內(nèi)徑處的磨損表面光滑，摩擦膜連續(xù)穩(wěn)定，顏色明亮，為“亮帶”的組織形貌，摩擦性能較好。
關(guān)鍵字: C/C復(fù)合材料；有限元；熱應(yīng)力；磨損表面
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
