Forming criteria for metal matrix composites

Rolling of metal matrix composites (MMC) is proposed as a consolidation technique. Rolling in the transverse direction to the fiber orientation is analyzed. Plasticity analysis is conducted using Hill's general yield criterion for anisotropic materials and the associated Levy-Mises equations modified for plane strain conditions. The slab method is used to calculate the macroscopic stresses in MMC's and the effects of rolling parameters on the principal stress ratio are investigated.; At the microscopic level, an elastic-plastic finite element formulation and computation procedure are presented. The principal stress ratio is suggested as a parameter that determines the tendency for void formation due to debonding and fiber breakage. Elastic-plastic finite element analysis is conducted to investigate the effects of principal stress ratio on the fiber-matrix interfacial stresses in the micromechanics model. The results of the analysis defines the deformed mesh and plastic zone propagation. The maximum tensile radial stress on the interface is presented as a function of volume fraction and principal stress ratio. Several techniques to avoid void formation and fiber breakage are discussed based on the results obtained. Future work to improve this analysis are recommended.