The investigation of several parameters during fiber push‐out micromechanical tests on the interfacial shear strength (ISS) of the BN interphase in SiC_f/SiC ceramic matrix composites (CMC) was undertaken to optimize experimental work. The SiC_f/SiC composites—candidate materials for jet engine components—were manufactured with varying fiber types and interlayer thicknesses. Experimental parameters explored included analyzing the effect of sample thickness on the success rate of micromechanical tests, the effect of fiber local environment whether at tow‐level (intra‐tow variability in ISS) or CMC architecture‐level (inter‐tow variability), the effect of nanoindenter flat‐punch tip size, and the effect of the interphase thickness itself. Over 1000 fiber push‐outs were performed and analyzed in this work—with data presented as cumulative distribution functions to compare and contrast samples. It was found that the ISS measured was strongly and statistically influenced by the underlying fiber roughness (interphase adherence), as well as its local fiber environment (e.g., number of nearest neighbors) only if the thickness of the interphase itself surpassed a threshold of 200 nm. Finally for thinner interphases, limited value was added to the CMC as the ISS measured was high and there was no effect from any local environment.

中文翻译：

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优化纤维推出方法以评估SiC / BN / SiC陶瓷基复合材料的界面破坏

为了优化实验工作，对纤维推出微机械测试中的一些参数对SiC _f / SiC陶瓷基复合材料（CMC）中BN相的界面剪切强度（ISS）进行了研究。碳化硅_˚F/ SiC复合材料（用于喷气发动机组件的候选材料）以不同的纤维类型和中间层厚度制造。探索的实验参数包括分析样品厚度对微机械测试成功率的影响，纤维局部环境的影响（无论是在丝束级（ISS中的丝束内变异性）还是在CMC体系结构级（丝束间变异性），纳米压头平冲头尺寸的影响，以及相间厚度本身的影响。在这项工作中，执行并分析了1000多个光纤推出-数据以累积分布函数的形式呈现出来，用于比较和对比样品。发现所测量的ISS受基础纤维粗糙度（相间粘附）及其局部纤维环境（例如，仅当相间厚度本身超过200 nm的阈值时。最后，对于较薄的相间，由于测量的ISS高，CMC的值增加了限制，并且不受任何本地环境的影响。