Simple Geometric Model for Assessing Whisker Orientation in Axisymmetric SiC‐Whisker‐Reinforced Composites

Abstract

The nonuniform crystal structure of SiC whiskers complicates the interpretation of X‐ray texture data collected from whisker‐reinforced composites. A simple model for assessing whisker textures in alumina matrix composites which is able to account for the mixed polytype structure of SiC whiskers is discussed. Synchrotron X‐ray radiation was used to quantitatively measure SiC whisker texture in hot‐pressed and hot‐forged Al2O3–SiC whisker composites. Pole figures of the 2.51 Å reflection ({111} cubic, (001) hexagonal) were obtained and compared to pole figures calculated from hypothetical whisker axis disribution describing the whisker orientation distribution within the axisymmetric composites. The X‐ray data suggest that the degree of reinforcement phase texture in hot‐worked specimens is dependent upon final specimen strain. The data also demonstrate that for conventionally hot‐pressed composites the whiskers are angularly distributed about the compression plane, having an average orientation which does not approximate a two‐dimensionally random distribution.