Thermal residual stress evolution in a TiC–50 vol.% Ni3Al cermet

Volume averaged thermal residual stresses in a TiC–50 vol.% Ni3Al cermet were measured over a temperature range from room temperature to about l250 K using in situ neutron diffraction. At room temperature, the thermal residual stresses in both the Ni3Al binder and the TiC particles were about 1.6 GPa. In the temperature range studied, the residual stress exhibited primarily elastic behavior during heating, followed by a non-linear cooling. The path dependency is attributed to a limited plastic flow and severe strain hardening in the Ni3Al binder phase below 900 K during cooling. Furthermore, the isothermal annealing of the cermet at l250 K for 10 h did not show any creep relaxation of residual stresses or development of interfacial phases. An elastic finite-element model was developed which approximately predicts the thermal residual stress evolution in the TiC–50 vol.% Ni3Al cermet studied.