The primary approach is to use a material that can undergo a stress-induced phase transformation at the interphase. When a matrix crack approaches the interphase, the stress field of the crack causes the interphase to undergo a volume decreasing phase transformation. This volume change produces local disintegra tion of the interphase and consequently debonding between the matrix and reinforcement. In this research, the tape-cast laminates, sandwich specimens, and fiber model systems have been fabricated and studied. Interfacial properties have been evaluated by the indentation technique, flexural test, and fiber push-out test.
Emphasis is on common clays, fly ash, bottom ash, and diatomaceous earth as raw materials.
Sol incorporation and gellation, with careful control of pH and rheology, is similarly being evaluated in fabrication, as is phosphate bonding. Combustible additives, such as sawdust, and expansive additives, such as vermiculite, are also being studied as means of decreasing density. Extruded honeycomb structures will be produced and evaluated. Y. Xu Dow Corning Corp. In the first phase of this investigation, several techniques for sample preparation and microanalysis were developed.