Growth of ternary composites from the melt: Part I

A simple constitutional supercooling analysis is given for predicting interface stability in plane front solidification of ternary alloys containing one, two, or three phases. It is concluded that polyphase composites can be grown from ternary alloys by plane front solidification provided thermal gradient is sufficiently high, growth rate is low, convection is low and kinetic undercooling is small. Calculated examples of conditions required for stability are given for three-phase alloys from the aluminum-rich corner of the Al-Cu-Ni system. It is seen that the most stable compositions (with respect to interface breakdown) lie nearly, but not exactly, on lines of two-fold saturation. Formerly Research Assistant, Massachusetts Institute of Technology, Cambridge, Mass.