In Situ Study of Peritectic Couple Growth Under Purely Diffusive Conditions

Abstract

Herein, in a microgravity campaign onboard the International Space Station, peritectic coupled growth (PCG) is studied by solidifying alloys of the peritectic transparent organic system TRIS–NPG under purely diffusive conditions. The experiment reveals that the formation of PCG begins with coagulated lateral bands comprising the peritectic phase at temperatures below the peritectic one. After reaching the growth front of the pro-peritectic phase, growth competition between both solid phases occurs such that the patches of the pro-peritectic phase, lamellae, and fibers/rods grow in the stated order, coupled with the peritectic phase. As the entire solidification process occurs during the initial transient stage, the diffusion coupling between the two solid phases is weak.