Texture analysis of the development of microstructure in Cu30 at.% Ni alloy droplets solidified at selected undercoolings

Abstract

For CuNi alloy droplets processed by containerless solidification under levitation, the crystallographic texture is strongly correlated with the microstructure seen in optical metallography and with the undercooling at which solidification started. Systematic analysis of the texture is useful in understanding the development of the microstructure, in particular whether it is dendritic or grain-refined. The variation, with undercooling, of orientation spread in dendritic samples enables texture measurements to be used to estimate the maximum undercooling of a droplet when temperature measurement is not possible. The contribution of dendrite break-up to the observed grain refinement is analysed, both for low and high undercoolings.