A review on functionally graded ceramic-metal materials

Fgms can be used to avoid problems associated with the presence of an interface in a material: stress singularities due to elastic or thermal property mismatch,poor adhesion,or unwanted reflections at the interface. theceramic/metal fgms can be designed to reduce thermal stresses and take advantage of the heat and corrosion resistances of ceramic and the mechanical strength,high toughnessgood machinability and bonding capability of metalswithout severe internal thermal stresses,also exhibit higher fracture resistance parameters resulting in higher toughness due to crack bridging in a graded volume fraction. most of the processes for fgm production are based on a variation of conventional processing methods which are already well established. methods that are capable of accommodating a gradation step include powder metallurgy,centrifugal casting,and thermal sprayingas well as various coating techniques. this review concluded the powder metallurgy (pm) as the most suitable technique certainly for mass production and up-scaling of the fgms. the selection was strengthen after considering the advantages of the technique such as process costeffectiveness,reliability of the practical implementation of the process and the high capability of the process to control the quality of the fgms.