PRESSURE INFILTRATION OF MOLTEN ALUMINUM INTO PREFORM OF GRANULATED WHISKERS

Preform deformation occurs often during the infiltration when metal ma trix composites are produced by squeeze casting. One of the means to o vercome the problem is to make the permeability large and the infiltra tion easy. Then, the granulated whisker preform was developed and the pressure infiltration phenomena of molten aluminum into the preform we re investigated by squeeze casting. The aluminum berate whiskers were prepared as a reinforcement. The permeability of the granulated whiske r preform was six times larger than that of the uniform preform in whi ch whiskers were distributed randomly and homogeneously. When the pres sure is applied, the molten metal first flows between the granules of whiskers to the bottom of the preform and then infiltrates into the gr anule of whiskers as the applied pressure increases. The pressure infi ltration phenomena were analyzed with the threshold pressure and the i nfiltration pressure. It became possible to suppress the preform defor mation using the developed preform having larger permeability than tha t of the uniform preform.