Reinforing Mechanism of Fiber-Reinforced Metals Considering Interfacial Stress Transfer

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The effects of interfacial shear mechanical properties on the tensile strength of SiC (SCS-6) fiber-reinforced Ti-15-3 alloy matrix composites have been examined. The interfacial shear mechanical properties were measured by thin specimen pushout technique which developed within this study. The interfacial shear debonding energy release rate was about 10 J/m^2 and shear sliding stress was 70-120 MPa.The origin of interfacial shear sliding stress was also obtained using the pushout test results and FEA.The result showed that the interfacial shear frictional sliding originated from (i) roughness at sliding interface, (ii) thermally induced clamping stress, and (iii) Poison's constrain effects. The interface roughness depends on the rteaction products and path of the debonding crack. Quantitative understanding of the origin of shear frictional stress was also carried out.The tensile strength of the composite was obtained theoretically using the properties of fiber, matrix, and interface. The theoretical prediction of the tensile strength agreed well with the experimental results. The obtained theoretical prediction was re-arranged as a from of "rule of mixture" to obtain tensile strength of various types of fiber-reinforced metals. The rule of mixture clearly demonstrated effects of interfacial shear mechanical properties and existence of optimum interfacial shear mechanical properties to obtain a maximum strength of fiber-reinforced metal matrix composites.