Observation of peritectic couple growth for a hyper-peritectic alloy under microgravity conditions

Abstract

Abstract Under specific conditions, peritectic alloys can form microstructures that behave similar to regular eutectic alloys, with two solid phases growing in a coupled manner directly from the melt. This so-called peritectic couple growth (PCG) is significantly affected by convection. Thus, Bridgman-type experiments were performed onboard the International Space Station using the transparent peritectic alloy, tris(hydroxymethyl)aminomethane–neopentyl glycol (TRIS–NPG). Under these purely diffusive conditions, the formation of PCG, its development over time, and its dependence on the applied process conditions were studied. In this paper, we provide novel insights into the appearance of PCG and the challenges associated with corresponding experiments.