A multiscale methodology quantifying the sintering temperature‐dependent mechanical properties of oxide matrix composites

Abstract

A novel methodology combining multiscale mechanical testing and finite element modeling is proposed to quantify the sintering temperature‐dependent mechanical properties of oxide matrix composites, like aluminosilicate (AS) fiber reinforced Al2O3 matrix (ASf/Al2O3) composite in this work. The results showed a high‐temperature sensitivity in the modulus/strength of AS fiber and Al2O3 matrix due to their phase transitions at 1200°C, as revealed by instrumented nanoindentation technique. The interfacial strength, as measured by a novel fiber push‐in technique, was also temperature‐dependent. Specially at 1200°C, an interfacial phase reaction was observed, which bonded the interface tightly, as a result, the interfacial shear strength was up to ≈450 MPa. Employing the measured micro‐mechanical parameters of the composite constituents enabled the prediction of deformation mechanism of the composite in microscale, which suggested a dominant role of interface on the ductile/brittle behavior of the composite in tension and shear. Accordingly, the ASf/Al2O3 composite exhibited a ductile‐to‐brittle transition as the sintering temperature increased from 800 to 1200°C, due to the prohibition of interfacial debonding at higher temperatures, in good agreement with numerical predictions. The proposed multiscale methodology provides a powerful tool to study the mechanical properties of oxide matrix composites qualitatively and quantitatively.

Phase field predictions of microscopic fracture and R-curve behaviour of fibre-reinforced composites

“…We find that the composite with interface debonding has the highest work of fracture, 21.7 J/m 2 , followed by the composite without interface debonding (20.4 J/m 2 ), with the bulk matrix giving 14.3 J/m 2 . Therefore, to improve the macroscopic fracture toughness of fibrereinforced composites, the fibre-matrix interface strength should be reduced, consistent with most toughening approaches used in ceramic fibre-reinforced composites [29]. However, to improve the strength of fibre-reinforced composites, a high fibre-matrix interface strength is required.…”

Dynamic oxidation mechanism of carbon fiber reinforced SiC matrix composite in high-enthalpy and high-speed plasmas

“…In response to uniaxial tension, all "dog-bone" specimens exhibited an elastic deformation after establishment of full contact between the "dog-bone" specimen and the tensile grip. This was followed by a typical fracture behavior [31]. The tensile fracture was successfully captured by in-situ SEM observation of the "dog-bone" specimen, as shown in Figs.…”

Phase field fracture predictions of microscopic bridging behaviour of composite materials

“…A weak interface between the matrix and the reinforcing material is beneficial to crack bridging. This strategy has been widely used to toughen brittle materials such as ceramic composites [57,58]. We quantify the effect of interface toughness G N I on the crack growth resistance of fibre-reinforced composites by varying its magnitude from 10 J/m 2 to 125 J/m 2 .…”