Processing of a Continuous Ceramic Fiber-Reinforced Iron Alloy

Abstract

Processing of a continuous ceramic fiber/iron alloy composite by powder metallurgy was investigated. The preparation of a continuous ceramic fiber-reinforced iron alloy is feasible by mixing of continuous ceramic fibers and iron alloy powders in an ultrasonic equipment with acetone, followed by hot isostatic pressing (HIPing) or hot pressing (HPing) at 1273 K. In HPing, a volume fraction of ceramic fiber in the composite in which ceramic fibers are distributed uniformly depends upon a diameter of ceramic fiber and a mean particle size of iron alloy powders. When a volume fraction of ceramic fiber is more than an optimum value, the excess fibers aggregate, resulting in nonuniform dispersion of ceramic fibers. On the other hand, nonuniform dispersion is also achieved because of the formation of ceramic fiber-free region when a volume fraction of ceramic fiber is less than the optimum value. In uniform dispersion of ceramic fibers, volume fraction of ceramic fibers in HIPed composite is higher than that in HPed composite. This is because ceramic fiber migration due to high stress occurs during HIPing. To obtain the composite with uniform dispersion of ceramic fibers, the specimen is to be uniformly deformed during HIPing.