Combined macroscopic and microscopic thermo-elasto-plastic stresses of functionally graded plate considering fabrication process

Functionally Graded Material (FGM) is a heterogeneous composite material th at consists of a gradient compositional variation of the constituent materi als from one surface of the material to the other. These continuous changes result in gradient material properties. Since ceramic has good heat resist ance and metal has high strength, FGM made by ceramic and metal can work at super high temperatures or under a high-temperature- difference field. It is a primary concern to reduce thermal stress by selection, of different ef fective material properties for the intermediate composition of the FGM and to prevent destruction by thermal stress. FGM is manufactured at a high te mperature and then residual thermal stresses are produced during cooling to room temperature. In this paper, the elastic-plastic thermal stresses indu ced in a ceramic-metal FGM plate (FGP) taking the fabrication process into consideration are discussed. The region near the heat resistant surface is produced by metal particle reinforced ceramic while the region near the coo ling surface is vice versa. As the metal and the ceramic near the middle re gion of the FGM are perfectly mixed, it is impossible to consider the parti cle-reinforced material. In this study, the FGP is divided into three regio ns. First, the region near the cooling surface is metal rich and then the m etal is considered as a matrix while the ceramic is considered as particles . Second, the region near the heat resistant surface is ceramic rich so tha t the ceramic is considered as a matrix while the metal is considered as pa rticles. Third, in the middle part between the previous two regions the met al and ceramic are perfectly mixed. In the third region macroscopic analysi s is considered because the difference between the volume fractions of the ceramic and the metal is small and it is difficult to consider one of them as a matrix or particles. The effects of the distribution parameter of the composition and the fabrication temperature on the thermal stress variation s are discussed.