Characterization of Solution and Precipitation Temperature in CMSX-4 Superalloy

AbstractNickel superalloys are used as the material for turbine blades due to their excellent mechanical properties at higher temperature. These excellent properties are a result of the microstructure, wich consist of their hard intermetallic (γ́) phase that is coherently embedded in the Ni-base (γ) phase. The mechanical properties of these superalloys largely depend on the size, morphology and distribution of the (γ́) phase. Both the (γ) and (γ́) phases have fcc crystallographic lattices, although a small misfit exist among them, which strongly influence the microstructural evolution during operation at high temperatures.A comprensive knowledge of the kinetics of these changes is necessary for the design of improved heat treatment processes and for a better understanding of the effects of high temperature service conditions on (γ́) evolution. This is particularly true for conditions for wich coarsening and particle dissolution of the (γ́) phase can occur.In the present study we determined the transformation temperatures, that is start and ending temperatures for solution and precipitation processes of γ́ by using Differential Thermal Analysis-(DTA-TG) measures in a CMSX-4 superalloy