Axial-piston pumps and motors which operate at high pressures (above 380 bar) typically incorporate a copper-alloy bushing paired with a steel piston. Manufacturers have a desire to eliminate such nonferrous heavy metals from their designs to reduce manufacturing complexity and cost. This paper explores possible alternatives to this material combination at high pressures. Simulations incorporating thermal and elastic material properties are computed using a Fluid Structure Thermal Interaction (FSTI) model. The results of simulation reveal how material properties interact to affect fluid film thickness and pressure generation during pump operation. An understanding of these phenomena points the way toward the selection of novel material combinations to improve the behavior of the piston/cylinder interface.