Infiltration of Saffil alumina fiber with AlCu and AlSi alloys.

摘要

Using the model system AlCuSi toinfiltrate a preform of alumina Saffil fibers, theeffects of five major variables on theinfiltration length were tested. The results aresummarized below. Preforms Saffil alumina can besuccessfully infiltrated by molten Al-cu and Al-Simatrix alloys under pressure in the range 0.8-3MPa. The L sub i was greater at a higher initialpreform temperature or higher pressure appliedwithin the range investigated. There is a limitin L sub i , for T sub f lower than the meltingtemperature. This limit becomes smaller when theV sub f of the preform is higher. As the pressurebeing applied by the melt surface rises it willreach a value sufficient to allow the front toadopt sufficiently sharp curvature to enter theinterfiber space. The value of this thresholdpressure will depend on the fiber volume fraction.The solute precentage was noted to have a verystrong effect on the infiltration length. This isinterpreted by assuming that the solute contentaffects the mode of solidification, where thesolid-liquid interface is not smooth and thedendritic multiplication mechanism can change the infiltration length.