Solidification behavior of Ni-base superalloy Udimet 720Li

A series of experiments have been conducted to investigate the solidification behavior of Ni-base superalloy Udimet 720Li. The results show that solidification of the alloy proceeds as follows: Liquid (L) -> L + gamma, L -> L + gamma + MC-Carbide, L -> L + gamma/gamma'-Eutectic, L -> eta-phase. The formation of gamma/gamma'-Eutectic is induced by the rejection of gamma' phase forming elements into the liquid during primary g phase precipitation. The limited solubility of Ti in primary g phase and gamma/gamma' Eutectic is the main reason that leads to the formation of h-phase. Boride and enrichment of boron have not been detected in the sample. The solidification is terminated by the formation of h-phase. gamma' phase precipitates in the matrix during subsequent cooling. (C) 2015 Elsevier B.V. All rights reserved.