Critical Matrix Yielding Stress and Interfacial Fracture in Forming of Metal Matrix Composite Wires

抄録

Effective manufacturing processes are vital in large-scale use of composite materials. Metal matrix composites have the potential to be formed into parts. To analyze the forming process, some yield criteria have been proposed assuming perfect bonding between fiber and matrix. The present paper provides a concise calculation of the yield condition taking into consideration the limited interfacial fracture strength to ensure swaging of a bundle of composite wires without fiber-matrix debonding. The yielding stress of the matrix must be constantly kept below a limit, most feasibly by heating. In the present analysis, Timoshenko's model is used to calculate the apparent stress distribution in a wire cross section under symmetric lateral loading. The yield function of Dvorak and Bahei-El-Din is applied to predict the initial yield. The stress concentration at the interface is determined by Goodier's method. Using the interface fracture strength as a criterion, the matrix yielding stress is limited to a critical value, beyond which interfacial bonding fails during the forming process. This concept and the ensuing results can be applied in the industrial forming of metal matrix composites.