【摘要】：顆粒增強(qiáng)鎳基復(fù)合材料具有各向同性,易于成型,成本低廉,應(yīng)用范圍廣等優(yōu)點(diǎn),采用原位合成法制備TiC_x增強(qiáng)Ni基復(fù)合材料具有粒子與基體結(jié)合牢固,孔隙率小,無(wú)明顯雜質(zhì)等優(yōu)點(diǎn),已成為當(dāng)前研究的熱點(diǎn)。本文基于改善顆粒增強(qiáng)鎳基復(fù)合材料的強(qiáng)韌性、耐磨性和抗氧化性的目的,以Ti_3SiC_2為先驅(qū)體材料,利用Ti_3SiC_2陶瓷容易發(fā)生拓?fù)浞磻?yīng)的特點(diǎn),采用固態(tài)擴(kuò)散方法原位合成TiC_x增強(qiáng)Ni基復(fù)合材料。研究TiC_x/Ni復(fù)合材料的微觀組織、力學(xué)性能、耐磨性和抗氧化性能,并進(jìn)一步探討其失效機(jī)理。研究結(jié)果表明:(1)研究高溫下Ti_3SiC_2陶瓷和金屬Ni反應(yīng):在1200℃時(shí),Ti_3SiC_2陶瓷和金屬Ni界面結(jié)合良好,界面生成兩層反應(yīng)層,但是在此條件下無(wú)法合成復(fù)合材料。在1300℃時(shí),通過(guò)擴(kuò)散反應(yīng)生成復(fù)合材料,研究了Ti_3SiC_2陶瓷和金屬Ni體積比不同時(shí)的顯微結(jié)構(gòu)。結(jié)果表明:當(dāng)Ti_3SiC_2和Ni體積比為2:1時(shí),復(fù)合材料以TiC_x、Ni16Ti6Si7三元相和Ni31Si12等Ni-Si化合物為主要相,含有少量Ni(Si)固溶體;當(dāng)Ti_3SiC_2和Ni體積比為1:1時(shí),由于拓?fù)浞磻?yīng),Ti_3SiC_2完全轉(zhuǎn)變成TiC_x,原位合成TiC_x顆粒增強(qiáng)Ni(Si)復(fù)合材料,并沒(méi)有其它雜質(zhì)相生成。(2)原位合成TiC_x增強(qiáng)Ni基復(fù)合材料的硬度值為663HV,彎曲強(qiáng)度為1234.30MPa±306.5 MPa;彎曲模量為147.629 kN·mm-2±19.28 kN·mm-2。利用掃描電鏡對(duì)樣品的三點(diǎn)彎曲斷口形貌進(jìn)行觀察,發(fā)現(xiàn)這種復(fù)合材料的斷裂形式主要是以韌性斷裂為主,并伴隨有少量的脆性斷裂斷口形貌。(3)研究了原位合成TiC_x增強(qiáng)Ni基復(fù)合材料在不同載荷作用下的滑動(dòng)摩擦磨損性能。在室溫下,這種復(fù)合材料的磨損失重和質(zhì)量磨損率隨載荷的升高而不斷增加,但增加的幅度都不大。且隨著載荷的增加,磨損表面上粘著和塑性變形的跡象逐漸加重。(4)研究了原位合成TiC_x增強(qiáng)Ni基復(fù)合材料在700、800、900℃下恒溫氧化性能。在高溫下,這種復(fù)合材料恒溫持續(xù)氧化20 h,氧化動(dòng)力學(xué)曲線基本符合拋物線規(guī)律,在700、800和900℃的氧化速率常數(shù)分別為1.51×10-4、7.07×10-4和4.52×10-3mg2·cm-4·min-1,氧化反應(yīng)的活化能為188.56 kJ·mol-1。試樣的氧化產(chǎn)物主要為TiO2,伴隨有少量的NiO和SiO2。
[Abstract]:Particle reinforced nickel matrix composites have the advantages of isotropy, easy forming, low cost and wide application. The TiC_x reinforced Ni matrix composites prepared by in-situ synthesis method have the advantages of solid particle and matrix bonding and low porosity. No obvious impurity and other advantages, has become the focus of current research. In order to improve the strength, toughness, wear resistance and oxidation resistance of particle reinforced nickel matrix composites, Ti_3SiC_2 was used as precursor material and Ti_3SiC_2 ceramics were used to easily produce topological reactions. TiC_x reinforced Ni matrix composites were synthesized in situ by solid diffusion method. The microstructure, mechanical properties, wear resistance and oxidation resistance of TiC_x/Ni composites were studied. The results show that: (1) the reaction between Ti_3SiC_2 ceramics and Ni at high temperature is studied. The interface of Ti3SiC2 ceramics and Ni is well bonded at 1200 鈩，

本文編號(hào)：2149378