Densification kinetics of uniaxially reinforced materials with porous matrices in free pressing
On the basis of a continual model of a porous body kinetic equations are derived, on the assumption that the densification of a composite is controlled by nonlinear viscous flow of the material of its matrix, describing the shrinkage of uniaxially reinforced materials during free hot pressing.
Kinetic laws are established governing the variation of the porosity of the matrix in a reinforced composite and the character of its distribution throughout the volume of the material in free hot pressing. Expressions are derived making it possible to calculate the maximum values of starting matrix porosity at which composites of various starting structures can be densified to a virtually nonporous condition.
Relationships have been established enabling maximum starting matrix porosities to be calculated at which composites of various starting structures can still be densified to a virtually nonporous condition.
It is shown that full densification of composites is more difficult to achieve in free hot pressing than in pressing in a rigid die.
KeywordsPorosity Shrinkage Kinetic Equation Viscous Flow Porous Body
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