固相反応によるニッケルアルミニウム青銅鋳物の非平衡偏析について

概要

論文の詳細を見る
When an alloy solidifies, the equilibrium composition of the originating solid phase differs in general from the composition of the liquid phase. Thus, segregation may take place, and the composition of the solid phase formed at different instant differs from the bulk compositons. In the case of the β to α phase transformation of Nickel Aluminium Bronze cast, as well as in the solidification of solid solution, the composition of the coexisting β and α-phase must change continuously. This change requires diffusion, which at best remains incomplete in the α-phase, because the diffusion rate in α-phase are comparatively low. The resulting non-equilibrium eutectoid remains in the alloy containing 9 to 10 pct Aluminium and 5 pct each of nickel and iron. Theoretical analysis has been also made for the degree of segregation, which depends on factors of nucleation rate of α-phase and cooling rate. It has been shown that under slow cooling conditions significant segregation is expected if the nucleation rate of α-phase is low.
Japan Foundry Engineering Societyの論文