Dm. Elzey et Hng. Wadley, A FIBER FRACTURE MODEL FOR METAL-MATRIX COMPOSITE MONOTAPE CONSOLIDATION, Acta metallurgica et materialia, 42(12), 1994, pp. 3997-4013
The consolidation of plasma sprayed monotapes is emerging as a promisi
ng route for producing metal and intermetallic matrix composites reinf
orced with continuous ceramic fibers. Significant fiber fracture has b
een reported to accompany the consolidation of some fiber/matrix syste
ms, particularly those with creep resistant matrices. Groves et al. [A
cta metall. mater. 42, 2089 (1994)] determined the predominant mechani
sm to be bending at monotape surface asperities and showed a strong de
pendence of damage upon process conditions. Here, a previous model for
the densification of monotapes [Elzey and Wadley, Acta metall. mater.
41, 2297 (1993)] has been used with a stochastic model of the fiber f
ailure process to predict the evolution of fiber fracture during eithe
r hot isostatic or vacuum hot pressing. Using surface profilometer mea
sured roughness data for the monotapes and handbook values for the mec
hanical properties of different matrices and fibers, this new model is
used to elucidate the damage dependence on process conditions, monota
pe surface roughness, and the mechanical properties both of the fiber
and matrix. The model is used to investigate the ''processibility'' of
several currently important matrix and fiber systems and to identify
the factors governing this. An example is also given of its use for th
e simulation of a representative consolidation process cycle. This app
roach to the analysis of a complex, nonlinear, time-varying process ha
s resulted in a clear understanding of the causal relationships betwee
n damage and the many process, material and geometric variables of the
problem and identified new strategies for its elimination.