SOLIDIFICATION PROCESSING OF HIGH-TEMPERATURE INTERMETALLIC EUTECTIC-BASED ALLOYS

This paper describes the role of solidification processing of high-temperature eutectic alloys in the development of high-temperature structural materials. Particular emphasis is placed on directional solidification of eutectic-based alloys using cold crucible Czochralski crystal growth. Alloys with melting temperatures up to 2250 degrees C were directionally solidified by this technique for study of the microstructure, phase equilibria and mechanical properties. The attributes and limitations of the Czochralski technique are compared with those of other methods for solidification of high-temperature alloys. The microstructures and fracture toughness data of directionally solidified in situ composites generated from Nb-Si and Cr-Nb alloy systems are presented. Property enhancements that can be achieved by directional solidification of high-temperature materials are discussed.