Role of material combination and new results of mechanical behavior for FG sandwich plates in thermal environment

•New numerical results of mechanical behaviors of FG sandwich plates in high temperature are presented.•Not all sandwich plates with FGMs face sheets possess similar mechanical behaviors and performance in high temperature.•A strong impact of severe high temperature affected the mechanical behaviors of sandwich plates is found.•Material combinations play a crucial role and significantly affect the mechanical behaviors of sandwich plates.•Present results may be helpful to the design of engineering application of FGMs especially in nuclear power plant.