铝硅酸盐纤维增强Al2O3-SiO2复合材料的制备与性能研究  

Research on fabrication and properties of aluminosilicate fiber-reinforced Al2O3-SiO2 composites

作　　者：王义 张翱 盛兵 周峰 向阳 程海峰[2] WANG Yi;ZHANG Ao;SHENG Bing;ZHOU Feng;XIANG Yang;CHENG Haifeng(PLA 96901,Beijing 100094,China;College of Aerospace Science and Engineering ,National University of Defense Technology, Changsha 410073,China)

机构地区：[1]中国人民解放军96901部队,北京100094 [2]国防科技大学空天科学学院新型陶瓷纤维及其复合材料重点实验室,湖南长沙410073

出　　处：《材料研究与应用》2019年第3期180-186,共7页Materials Research and Application

基　　金：国家自然科学基金资助(项目号51602347)

摘　　要：对Al2O3-SiO2凝胶的无机化与烧结特性进行了研究,结果表明:Al2O3-SiO2凝胶主要由勃姆石(boehmit)和无定形SiO2组成,经500℃煅烧后boehmit分解形成γ-Al2O3,1200℃煅烧后γ-Al2O3转变为(δ,θ)-Al2O3,1300℃煅烧后(δ,θ)-Al2O3和无定形SiO2反应生成莫来石(mullite);随着烧结温度的升高,Al2O3-SiO2陶瓷的收缩率逐渐升高,孔隙率逐渐降低,相对密度逐渐升高.采用溶胶-凝胶工艺制备了三维铝硅酸盐纤维增强Al2O3-SiO2复合材料,并对热处理温度进行了优化,研究结果表明:随着热处理温度的升高,复合材料的弯曲断裂模式逐渐由韧性断裂转变为脆性断裂,复合材料断面拔出纤维长度逐渐缩短直至消失;热处理温度为1100℃时制备的复合材料的力学性能最优,其弯曲强度、剪切强度和断裂韧性分别为90.0±6.8 MPa,11.1±1.0 MPa和3.6±0.2 MPa·m^1/2.The mineralization and sintering behaviors of Al2O3-SiO2 gels were investigated. Gels were composed of boehmit and amorphous SiO2. After calcined at 500 ℃, the boehmit decomposed to γ-Al2O3. After calcined at 1200 ℃, γ-Al2O3 changed to(δ, θ)-Al2O3. After calcined at 1300 ℃,(δ, θ)-Al2O3 reacted with amorphous SiO2, and mullite occurred. As sintering temperature increased, coefficient of shrinkage and relative density of Al2O3-SiO2 ceramics were all increased gradually. Three-dimensional aluminosilicate fiber-reinforced Al2O3-SiO2 matrix composites were fabricated by sol-gel process. Effects of sintering temperature on the density, microstructure and mechanical properties of the composites were investigated. As sintering temperature increased, fracture mode of the composites changed from toughen to brittle, with the pullout fiber shortening gradually and eventually disappearing at the composite fracture surface. Composites fabricated at 1100 ℃ displayed the highest mechanical properties. The average flexural strength, interlaminar shear strength and fracture toughness of those composites, with the density of 1.92 g/cm3, were 90.0±6.8 MPa,11.1±1.0 MPa and 3.6±0.2 MPa·m1/2, respectively.

关 键 词：氧化物 复合材料 溶胶-凝胶工艺 微观结构 力学性能 

分 类 号：TB323[一般工业技术—材料科学与工程]