Element distribution in the macro- and microstructure of nickel base superalloy CMSX-4

In the nickel base superalloy CMSX-4 phase compositions were determined with high lateral resolution by energy dispersive X-ray analysis inside a transmission electron microscope. After standard heat treatment, considerable enrichment of elements Re and W was detected in the matrix of dendrites compared to interdendritic regions. Equilibrium compositions of γ′ and matrix phase and the γ′ volume fraction depended strongly on temperature. In creep specimens tested at 1123 K, directed diffusion of elements with large atomic radius occurred in the pressure gradient between matrix channels with different orientation to the load axis.