Solidification microstructure of Cu–Cr and Cu–Cr-In alloys

Abstract

Solidification microstructure of Cu–Cr and Cu–Cr-In alloys has been characterized using scanning electron microscopy in the present work. Thermodynamic database has been established for the Cu–Cr binary system and Cu–Cr-In ternary system. Solidification behaviors of the two alloys have been simulated using the thermodynamic parameters based on Scheil model. The results show that the primary Cr phases with long and thin dendrites can be observed between Cu matrix grains for the Cu–Cr alloy, and the ‘flower-like’ coarsen dendrites primary Cr phases of the Cu–Cr-In alloy exist in the triangular grain boundary areas. The weight percent of indium element in the liquid phase of the Cu–Cr-In alloy during solidification continuously increases up. This will enlarge the solidification temperature range from 6 °C to 214 °C resulting in longer time for the dendrite growth and the alloying element indium with low melting point tends to segregate to the grain boundary region.