THE INFLUENCE OF FABRICATION PARAMETERS ON THE DEFORMATION-BEHAVIOR OF THE PREFORM OF METAL-MATRIX COMPOSITES DURING THE SQUEEZE-CASTING PROCESSES

Through a series of experiments with preforms that had a randomly-orie nted fiber distribution, the deformation of the preform and the tensil e strength of the metal-matrix composites were investigated with varia tion of processing parameters such as the punch velocity, the amount o f binder, the preform temperature, the fiber volume fraction and the a pplied pressure. Experimental data are presented on the injection of a luminum-alloy melts into preforms composed of delta-alumina short fibe rs with a silica binder. The preforms were prepared from liquid slurry using the vacuum filtration process. The base material used in this s tudy was A12024, having poor fluidity compared with a casting aluminum alloy. Scanning electron and optical micrographs are also presented f or investigating the effects of processing parameters on the microstru ctures of the metal-matrix composites. Recommendations are put forward concerning the optimization of the microstructure through control of the processing parameters.