Crystals Of Different Dispersity Competition In Invariant Reactions L+А+В=С, L+А=В+С

Abstract:

Computer model of T-x-y diagram is used as an instrument to design the microstructures of heterogeneous materials [1]. Not only the trajectories of phases for the arbitrarily taken alloy in the system with many ternary compounds may be reproduced, but the material balances with the distinguishing of crystals with different prehistory are shown. Main problem in the construction of phase diagram is the appearing of the ternary compounds in subsolidus. Competition of the primary crystals A1 and the eutectic ones Ae was investigated for the quasiperitectic reaction L+A=B+R with the binary incongruently melting compound R=AmC of fixed composition. Concentration field of 4-phase reaction L+A=B+C with competition of primary A1 and eutectical Ae crystals should be divided into 3 parts with the microstructures A1+Ae+M, A1+M, Ae+M. Isopleths with the masses equivalency А1=Ае, Ае=АQ, А1=АQ & Аex=АQ were found, where AQ – total quantity of crystals A participated in reaction L+A=B+R, Аex – quantity of A crystals, that were exceeded and have been left after the reaction. The same investigation have been prolonged for the systems with the ternary compounds and with the peritectic reaction L+I+J=K.New information about 3-phase region with transformation was received (it may be divided into the parts: without the phase mass increment sign changing, with 1 phase mass increment sign changing, with 2 phases mass increment sign changing, with 3 phases mass increment sign changing; in the last case all surfaces of two-phase reactions have the common directing curve).

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