Effect of Microstructure on the Mechanical Behavior of Continuous‐Fiber‐Reinforced Ceramic‐Matrix Composites

Abstract

The mechanical behavior of a unidirectional continuousfiber ceramic-matrix composite (CFCMC) was correlated with matrix-rich channels in the microstructure. A large population of CFCMCs was prepared via alkoxide infiltration, which incorporated either uncoated Nicalon™ fibers (64 samples) or BN-coated fibers (118 samples). No structure/property correlation was observed for the uncoated composites, because of the uniformity of the microstructure. For the BN-coated composites, both the flexure strength and work of fracture (WOF) were correlated with oriented matrix-rich channels. The channels were <90 µm wide and were distributed throughout the cross section. The BN-coated CFCMCs exhibited laminate-like behavior: the strength was statistically higher when the channels were aligned parallel with the applied load and the WOF was statistically higher when the channels were perpendicular to the load. Grouping the specimens on the basis of channel orientation, relative to applied load, reduced the variance in strength and WOF. This categorization also resulted in consistent, predictable failure behavior. This observation implies that prior CFCMC data that do not consider microstructure orientation may show wider scatter in mechanical behavior than is warranted.

Novel Technology for X‐ray Mapping of Ceramic Microstructures

“…The synthesis by sol-gel methods and the mechanical properties of this composite have been reported elsewhere. 6 The fibers are commercial SiC (Nicalon, Nippon Carbon, Tokyo, Japan), and the composite has a fiber loading of 50%. The size distribution and the volume fraction both have been confirmed by image analysis.…”

Nano-aluminum-phosphate via a polymerized organic–inorganic complex route

“…Fiber-reinforced and laminated ceramic composites exhibit graceful failure that can be used in many applications [1][2][3]. In such composite it is desirable to produce a weak interface and/or a layer that facilitates propagating crack deflection hence avoids catastrophic failure [4][5][6][7].…”

A finite element reduced‐order model based on adaptive mesh refinement and artificial neural networks

“…Several families of multi-fidelity models exist, which include Surrogate Models [21,36,48], hierarchical multi-fidelity approaches [24,22,31]. These can be based on several approaches which include response surfaces [12,26,46] and Kriging methods [29,27,34]. The method here proposed can be understood, and used as, a multi-fidelity approach, although it will not be applied as such in this work.…”