Influence of 2-6% Re additions has been investigated on the solidification phenomenon of a Ni base superalloy, In718. The solidification of each alloy proceeds in the order of primary γ, eutectic (γ+NbC) and eutectic (γ+Ni2Nb). Higher additions of Re increase the volume fraction of primary γ and enlarge the secondary dendrite arm spacing. The influence of cooling rates at 1, 10 and 100K/min has also been studied on the solidification process of the alloy containing 3.5% Re. With increasing cooling rate, the crystallization start temperatures of primary γ and eutectic phases decrease and the volume fraction of NbC and Ni2Nb increase. EPMA analysis revealed that the distribution of alloy elements in microstructure also changed depending on cooling rate. The redistribution of alloy elements during solidification was evaluated by Clyne-Kurz and Ohnaka theories.
!!!All Science Journal Classification (ASJC) codes