本文選題：Ti-Al基復合材料 + 軸承��； 參考：《濟南大學》2014年碩士論文

【摘要】：由于Ti-Al合金具有高溫力學性能好、比強度高等優(yōu)點，適用于真空、航空航天等特殊領域，但是其脆性大、耐磨性差，限制了其應用。本文擬采用合金化方法提高其力學性能，通過在TiAl基體中添加Cr、Nb等元素提高其強韌性，添加固體潤滑劑（CaF2、BaF2）改善其摩擦磨損性能。 采用真空熱壓燒結方法制備出輕質、耐磨的Ti-Al基自潤滑軸承材料。通過對軸承材料的摩擦學設計、材料的制備、力學性能測試，探討了該自潤滑軸承材料的摩擦磨損性能。 制備出力學性能和摩擦磨損性能良好的滑動軸承材料，并研究了該材料的密度、抗彎強度、硬度、斷裂韌性等力學性能。研究發(fā)現：隨著固體潤滑劑的增多，復合材料的密度呈現出先增大后減小的趨勢；材料的硬度隨著固體潤滑劑的增多逐漸下降，未添加潤滑劑時，基體材料的硬度為51HRC，而添加質量分數為15%固體潤滑劑后，硬度下降到37HRC。在潤滑劑添加量為0~10%內，彎曲強度和斷裂韌性均隨著潤滑劑的增多而上升，而當固體潤滑劑添加量超過10%時，材料的彎曲強度和斷裂韌性均隨著潤滑劑的增多而下降。 分別在室溫和650℃下，對自潤滑Ti-Al基復合材料的摩擦磨損性能進行了研究。研究發(fā)現，摩擦因數隨著固體潤滑劑的增多而下降，CaF2和BaF2起到了良好的潤滑作用，而且Ti-Al基復合材料在高溫下的摩擦磨損性能優(yōu)于室溫下。分別添加質量分數為10%和12%的固體潤滑劑時，材料的綜合性能較好，微觀磨損形貌較平整，摩擦磨損性能較好。在650℃高溫下，當潤滑劑BaF2-CaF2質量分數為10%時，材料的磨損率能最低，達到0.29×107cm3N-1m-1。在650℃下，分別研究了磨損率和摩擦系數隨著轉速和載荷的變化規(guī)律。發(fā)現：磨損率、摩擦因數均隨轉速的增大而增大，磨損率、摩擦因數均隨載荷的增大而增大。通過分析Ti-Al基復合材料的微觀磨損形貌，發(fā)現其主要磨損形式為黏著磨損，還有一定的表面變形。 通過Solidworks三維建模和ANSYS仿真分析，在600℃下，20MPa壓力下，，對比研究了Ti-Al基自潤滑材料和淬硬軸承鋼GCr15（滑動表面度0.003~0.01mm的硬鉻）的摩擦磨損性能。研究發(fā)現：Ti-Al基自潤滑材料的摩擦性能也是極其優(yōu)越的，在摩擦一段時間后，Ti-Al材料產生的最大溫度值比淬硬軸承鋼要小近3倍，最大應力值小2.5倍。
[Abstract]:Ti-Al alloy is suitable for vacuum, aerospace and other special fields because of its good mechanical properties at high temperature and high specific strength. However, its brittleness and poor wear resistance limit its application. In this paper, alloying method is used to improve the mechanical properties of TiAl. The strength and toughness of the composites are improved by adding CrNb and solid lubricant CaF2BaF2) to improve their friction and wear properties. Ti-Al-based self-lubricating bearing materials with light weight and wear resistance were prepared by vacuum hot pressing sintering. The friction and wear properties of the self-lubricating bearing material were discussed by tribological design, preparation of the material and testing of the mechanical properties. A sliding bearing material with good mechanical properties and friction and wear properties was prepared and its mechanical properties such as density bending strength hardness and fracture toughness were studied. It is found that the density of composites increases first and then decreases with the increase of solid lubricants, and the hardness of composites decreases with the increase of solid lubricants. The hardness of the matrix material is 51 HRC, but the hardness of the matrix material decreases to 37 HRC after adding 15% solid lubricant. The flexural strength and fracture toughness of the material increased with the increase of lubricant, but when the amount of solid lubricant was more than 10%, the flexural strength and fracture toughness of the material decreased with the increase of lubricant. The friction and wear properties of self lubricating Ti-Al matrix composites were studied at room temperature and 650 鈩

本文編號：1901468