ZrO 2 fiber-matrix interfaces in alumina fiber-reinforced model composites

Effect of Y2O3 addition on the phase composition and crystal growth behavior of YSZ nanocrystals prepared via coprecipitation process

“…Due to the exceptional properties, such as inherent oxidation resistance, high thermal expansion coefficient, low thermal conductivity, excellent thermal stability and high ionic conductivity, zirconia find wide applications in high-temperature structural materials [1,2], thermal barrier coatings [3,4], oxygen sensors [5,6], interferometric filters [7], and electrolyte for solid oxide fuel cells (SOFCs) [8,9]. It is generally known that pure zirconia exists in three crystallographic phases: low-temperature monoclinic phase (m-ZrO 2 , space group P2 1 /c), intermediate-temperature tetragonal phase (t-ZrO 2 , space group P4 2 /nmc) and high-temperature cubic phase (c-ZrO 2 , space group Fm3m).…”

Influence of Ti3SiC2Fiber Coating on Interface and Matrix Cracking in an SiC Fiber‐Reinforced Polymer‐Derived Ceramic

“…The fiber/matrix interface was characterized by fiber push-out tests [30][31][32] using a universal test device equipped with a load unit, holder positioning system, and an optical microscope. The sample plates with a thickness ranging from 0.2 to 0.4 mm were indented with a cylindrical flat-ended punch (d ¼ 120 mm) in a displacement-controlled mode at a rate of 1 mm s À1 .…”

Research Progress on Micro-mechanical Property of Continuous Fiber-reinforced Ceramic Matrix Composites

“…7 Typical features of the load-deformation curve of minicomposites [39] 图 8 (a)单纤维顶出实验实施过程示意图; (b)典型纤维顶出 实验载荷-位移曲线; SiC f /SiC 复合材料顶出纤维压头正面(c) 和背面(d)SEM 照片 [43] Fig. 8 (a) Schematic drawing of fiber push-out measurement; (b) Typical load-displacement push-out test curve; SEM images of the frontside surface (c) and backside surface (d) of SiC f /SiC minicomposite after fiber push-out test using a flat punch indenter [43] 度和脆性使包含数根完整纤维的薄片样品制备困难; ②薄片在研磨制备过程中容易破坏复合材料的力学 环境, 造成界面结合强度的变化甚至界面脱粘, 影响 形, 后面的曲线段对应纤维/基体界面脱粘过程 [45] 。 根据 Shear-lag 模型即可计算复合材料的界面结合 强度 [10][11][12][13][14][15][16][17][18][19]28,34,[45][46] :…”

“…研究等方面取得了丰硕成果, 但到目前为止, 仍然 难 以实 现精确 的力 学性能 仿真 和力学 行为 预判, CFRCMCs 组分、微观结构和宏观力学性能间本构 关系尚未精确构建, 这主要是因为 CFRCMCs 中各 组分原位微观力学参量的缺失。CFRCMCs 中各组 分的原位微观力学参量(主要包括纤维与基体的模 量、韧性, 界面结合强度等)既决定了 CFRCMCs 的 宏观力学性能, 又是宏观力学数值仿真的关键输入 参量 [6][7][8] 。长久以来, CFRCMCs 中各组分微观力学 参量的测量一直是难点问题, 这一方面由于陶瓷材 料固有的脆性使小尺度微观力学测试样品制备困难, 另一方面由于微观力学参数测试手段与理论的不完 善 [9] , 导致 CFRCMCs 微观力学研究工作进展相对 缓慢。 近年来, 随着以纳米压痕为代表的纳米力学测 量技术和以聚焦离子束(FIB)为代表的微纳加工技 术的快速发展, CFRCMCs 原位微观力学研究工作 取得显著进步, 并在 CFRCMCs 宏观力学性能研究 工作中发挥了重要作用 [10][11][12][13][14][15][16][17][18][19][20][21][22][23] 中纤维与基体的原位模量 [24][25][26][27] , 测量过程简单易操 作, 可以真实地反映 CFRCMCs 中纤维与基体的原 位力学参量信息, 相对于传统通过纤维与基体宏观 力学测试方法获取的力学参量更加准确。测量过程 如下: 对 CFRCMCs 进行抛光处理, 在纳米压痕成 像系统辅助下, 分别定位纤维与基体区域, 采用 Berkovich 压头进行加载, 根据 Oliver-Pharr 定律计算 测量样品的弹性模量 [24] : [10] , 采用纳米压痕测量的…”

“…1 (a) Young's modulus of the AS fiber in AS f /SiO 2 composites prepared at different temperatures as a function of penetration depth; SPM images of the nanoindentation imprints of AS f /SiO 2 composites fabricated at 600℃ (b) and 1200℃ (c) [10] 十兆帕)复合材料中 AS 纤维的模量均随着压入深度 [10] Fig. 2 Youngs modulus of the SiO 2 matrix in AS f /SiO 2 composites prepared at different temperatures as a function of penetration depth [10] 的 CFRCMCs 组分与微观结构演变信息。同样以 AS f /SiO 2 复合材料为例 [10] , [29] 、纤维切口法 [30][31] 和基体单体陶瓷单边切口梁法 [12] [18,32] : [32] Fig. 3 Radial cracks originating at the edges of a Berkovick indentation for carbide coating [32] [11,18,33] 。单边切口微梁法首先用 FIB 制备出如图 4(a)所示的测试样品 [18] , 样品尺度为微 米量级。测试样品上有一预制微裂纹, 采用纳米压 痕对其加载, 直至样品断裂, 根据式(3)即可得到材 料的原位断裂韧性 [18] :…”