The Microstructural Characteristics And The Morphology Of Fracture Surface Of Metal/Metal Functionally Gradient Material

With the development of preparation technology, people have begun to realize the importance of metal-metal fuctionally gradient materials(FGM). Up to now, the researches about metal-metal FGM by co-sedimentation under low temperature are insufficient, and most of researches are concentrated upon the design or fabrication. There is an empty space in the data about the microstructure of the metal-metal FGM . It is well known that macro mechanics, physical and chemical performances of materials are determined by their microstructures, cystal structures and chemical compositions. Therefore, it is very important for the study of microstructures.The dissertation briefly introduces the beginning , token , designing , fabrication, appraise, testing, application and development of fuctionally gradient materials. Furthermore the discourse gives the meaning, major work, innovation , feature about the project , the materials experimental procedures, and so on.In the present work, the chemical distributing , the microstructure characteristics and the fractorgraphy analysis of metal/metal FGM are studied systematically by using electron probe microstructure analysis(EPMA) , scanning electron microscopy(SEM) and energy dispersive X-ray analysis (EDS). As a result, some ideas about the fabrication are put forward.The EPMA experiment results show that the main element such as W, Mo, Ti, Ni, Cu, Fe element are changed gradually in W-Mo and W-Mo-Ti FGM. In the layer rich in W, the grain are intervained and are mixed mechanismly. The same is to the layer rich in Mo and W-Mo. These grain felt up by some sinter. In Mo-Ti layer rich in Mo, the grains are also mixed mechanismly. Ni, Cu, Fe element assembled at interface. Ni melt by Cu plays an vital role in sinter effect. The microstructure characteristics result show that the compactness of W-Mo and W-Mo-Ti FGM is good. Different element in some interface change in evidence, but different element in other interface change gradually. The interface often have some hole and a mass of one element. In W-Mo FGM, because the different rimetemperature, the size of Mo grain differ from the size of W. In W-Mo-Ti FGM , Mo-Ti layer rich in Ti, there are more polygonal a . However, in layer rich in Ti, there are more polygonal a -Ti . The fractorgraphy analysis show that in the layer rich in W and Mo, the feature of fracture is brittle fracture which follow the bordline of crystal. In sections rich in the felt metal, the feature of fracture is ductile fracture. In W-Mo layer, the feature of fracture are brittle fracture and some ductile fracture. In Ti layer, the feature of fracture is brittle fracture which pass through the crystal. In Mo-Ti layer, the feature of fracture is brittle fracture which pass through the bordline of crystal, but the feature of fracture is brittle fracture in the bordline of crystal.The math model of co-sedimentation is established and the calculation results are gained. In contrast with the experiment results, some advices about the fabrication are supposed to W-Mo-Ti FGM.