Thermoelastic behavior in Ca2SiO4 solid solutions

Dicalcium silicate solid solutions (C2S(ss)) doped with Na2O, Al2O3, and Fe2O3 were examined by high-temperature optical microscopy, Surface deformation caused by a possible martensitic transformation between alpha'(L) and beta phases was observed in situ under the microscope during temperature changes, indicating that the transformation was thermoelastic, Both the start and finish temperatures of the alpha'(L)-to-beta and beta-to-alpha'(L) transformations decreased with increased Na:(Na + Ca) ratio, Because of the athermal nature of the alpha'(L)-to-beta transformation, the alpha'(L) phase, when cooled below the finish temperature, should have been completely converted to the beta phase.