A turbine disk and blade assembly comprises a turbine disk including a plurality of disk posts extending radially therefrom and a plurality of disk slots between adjacent disk posts. The turbine disk is of a first material having a first coefficient of thermal expansion. The assembly further comprises a plurality of turbine blades. One of the turbine blades is received in each disk slot. The turbine blades are of a second material having a second coefficient of thermal expansion. The assembly further comprises a plurality of seal plates, wherein one of the seal plates is positioned in each disk slot radially inward of the turbine blade. The seal plates are of a material having a coefficient of thermal expansion substantially similar to that of either the disk posts or the turbine blade.