本文選題：自潤滑 + 微孔結(jié)構(gòu)��； 參考：《濟南大學(xué)》2015年碩士論文

【摘要】：熔滲型自潤滑復(fù)合材料是運用仿生摩擦學(xué)知識研究出的一種自潤滑材料。該復(fù)合材料的制備過程可以分為兩個部分:(1)燒結(jié)制備具有微孔結(jié)構(gòu)的網(wǎng)絡(luò)基體;(2)真空壓力熔滲固體潤滑劑。在工作過程中,要求微孔基體具有足夠的強度,以承受載荷;而潤滑劑的主要作用是降低摩擦界面的摩擦系數(shù),以保證潤滑性。微孔基體的微觀結(jié)構(gòu)是保證復(fù)合材料潤滑性的前提,因為微孔結(jié)構(gòu)(如微孔大小、分布及形狀)是決定浸滲固體潤滑劑的數(shù)量、潤滑劑分布的均勻性及在摩擦界面是否能夠形成潤滑膜的關(guān)鍵。本文以熔滲型自潤滑復(fù)合材料基體的微孔結(jié)構(gòu)為研究對象,基于均勻化理論和有限元分析方法,建立微孔單胞模型,對孔隙度、微孔結(jié)構(gòu)進行仿真分析�；谌蹪B型自潤滑復(fù)合材料的性能要求,研究了孔隙度、微孔形狀、孔徑分布等結(jié)構(gòu)特征參數(shù)對復(fù)合材料宏觀性能的影響;根據(jù)復(fù)合材料基體的設(shè)計原則,進行基體材料的組分組成及組分比設(shè)計,采用粉末冶金燒結(jié)法制備出微孔基體,對其進行了微觀結(jié)構(gòu)和性能表征。根據(jù)對熔滲型自潤滑復(fù)合材料微孔基體的理論分析結(jié)果可知,孔隙度是復(fù)合材料的一個重要結(jié)構(gòu)特征參數(shù),其與強度、硬度和自潤滑性能有著緊密的聯(lián)系�？紫抖扰c組成基體材料的粉末顆粒直徑無關(guān),只與粉末顆粒的形貌及排列方式有關(guān),且當(dāng)顆粒形貌為非球形時,燒結(jié)體的孔隙度較小;隨著特征值的不斷增大,孔隙度逐漸增加,而相對密度逐漸減小;隨著孔隙度的不斷增大,復(fù)合材料的相對彈性模量逐漸減小,泊松比逐漸增大,而抗壓強度呈指數(shù)下降。為保證復(fù)合材料力學(xué)性能和自潤滑性能的要求,微孔基體的孔隙度應(yīng)控制在15%-30%范圍內(nèi)。單胞模型的有限元仿真分析表明:微孔形狀分別為圓形、三角形、四邊形及六邊形時,隨著載荷的不斷增大,各種微孔形狀的單胞模型產(chǎn)生的Mises等效應(yīng)力值和應(yīng)變值不斷增大,但增大的速率均不同,即圓孔增大速率較慢,六邊形較快;當(dāng)位移載荷相同時,隨著孔隙度的增大,單胞模型產(chǎn)生的等效應(yīng)力增大,而等效應(yīng)變減小。綜合分析可知,微孔形狀為圓形和方形時綜合性能最好。以FeCrWMoV合金粉末為金屬相,TiC粉末為陶瓷相,同時添加一定體積分?jǐn)?shù)的復(fù)合造孔劑,采用粉末冶金燒結(jié)法制備出微孔基體。結(jié)果表明:燒結(jié)體微孔形狀規(guī)則(主要呈圓形或方形),孔隙分布均勻,且互相貫穿成網(wǎng)絡(luò)狀;隨著復(fù)合造孔劑體積分?jǐn)?shù)的增加,燒結(jié)體的孔隙度不斷增大;隨著孔隙度的不斷增大,燒結(jié)試樣的壓潰強度逐漸降低;保溫時間影響燒結(jié)試樣的微孔形狀,當(dāng)保溫時間為60min時得到試樣的微孔形狀主要呈圓形和方形,且壓潰強度較高。
[Abstract]:Infiltration self-lubricating composite is a self-lubricating material developed by using bionic tribology. The preparation process of the composite can be divided into two parts: 1) sintered to prepare the network matrix with microporous structure and 2) vacuum pressure infiltration solid lubricant. In the working process, the microporous matrix is required to have sufficient strength to withstand the load, and the main function of the lubricant is to reduce the friction coefficient of the friction interface to ensure the lubricity. The microstructure of the microporous matrix is a prerequisite for ensuring the lubricity of the composite, because the micropore structure (such as the size, distribution and shape of the micropore) determines the amount of solid lubricant impregnated. The uniformity of lubricant distribution and the key to the formation of lubricating film at the friction interface. Based on the homogenization theory and finite element analysis method, the microporous cell model is established, and the porosity and micropore structure are simulated and analyzed. Based on the performance requirements of infiltrated self-lubricating composites, the effects of structural characteristic parameters such as porosity, micropore shape and pore size distribution on the macroscopical properties of composites are studied. The composition and component ratio of the matrix were designed. The microporous matrix was prepared by powder metallurgy sintering method. The microstructure and properties of the matrix were characterized. Based on the theoretical analysis of the microporous matrix of the infiltrated self-lubricating composite, the porosity is an important structural characteristic parameter of the composite, which is closely related to the strength, hardness and self-lubricating properties. Porosity has nothing to do with the diameter of powder particles, but only depends on the morphology and arrangement of powder particles. When the particle morphology is non-spherical, the porosity of sintered body is smaller, and with the increasing of characteristic value, the porosity of the sintered body increases with the increase of the characteristic value. With the increase of porosity, the relative modulus of elasticity decreases, the Poisson's ratio increases, and the compressive strength decreases exponentially. In order to meet the requirements of mechanical properties and self-lubricating properties of composites, the porosity of microporous matrix should be controlled in the range of 15-30%. The finite element simulation analysis of the cell model shows that when the shape of the micropore is circular, triangular, quadrilateral and hexagonal, with the increasing of the load, the force and strain value of the Mises effect produced by the unit cell model of various micropore shapes increase continuously. But the rate of increase is different, that is, the increase rate of circular pore is slower, the hexagonal is faster, and when the displacement load is the same, with the increase of porosity, the equivalent stress produced by the unit cell model increases and the equivalent strain decreases. The comprehensive analysis shows that the comprehensive performance is the best when the shape of the micropore is circular and square. The microporous matrix was prepared by powder metallurgy sintering with FeCrWMoV alloy powder as metal phase tic powder as ceramic phase and adding a certain volume fraction of composite pore-forming agent. The results show that the micropore shape of the sintered body is regular (mainly circular or square, the pore distribution is uniform, and the porosity of the sintered body increases with the increase of the volume fraction of the compound pore-making agent, and the porosity of the sintered body increases with the increase of the volume fraction of the compound pore-making agent. With the increase of porosity, the crushing strength of the sintered sample decreases gradually, and the holding time affects the micropore shape of the sintered sample. When the holding time is 60min, the micropore shape of the sintered sample is mainly round and square, and the crushing strength is higher.
【學(xué)位授予單位】：濟南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB33

【參考文獻】

相關(guān)碩士學(xué)位論文 前1條

1 王贏利;新能源汽車白車身結(jié)構(gòu)拓?fù)浼俺叽鐑?yōu)化設(shè)計[D];大連理工大學(xué);2012年

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