文摘
A new in-house designed series of Ni based superalloys with stepwise increased Re and Ru additions has been investigated, to systematically determine the influence of Re and Ru on x3b3;/x3b3;′-microstructure and high temperature creep properties. Improved creep resistance and thus also a higher alloy temperature capability of up to 87 K/at. % was found for additions of Re. Additions of Ru revealed a lower temperature capability improvement of up to 38 K/at. % for low Re-containing second generation alloys. However, in third and fourth generation alloys with higher Re-contents, no significant influence of Ru on creep rupture strength was observed. The creep properties are discussed with respect to the x3b3;′-volume fraction, x3b3;′-size and x3b3;′-coarsening rate, as well as the x3b3;/x3b3;′-lattice misfit and the x3b3;/x3b3;′ partitioning coefficient of the different Re and Ru containing alloys. The presented data shows, that these microstructure parameters are strongly influenced by additions of Re, but only marginally by additions of Ru. A further influence on creep rupture strength is given by the solid solution hardening of the x3b3;-matrix, which is discussed based on solid solution hardener concentrations either experimentally derived or calculated from ThermoCalc data.