Microstructure And Mechanical Property Of The Joint Between Cermets And Metals Bonded By The FAPAS Process

Field Activated and Pressure Assisted Synthesis as a new material process which is carried out in the condition of multi-physical coupling fields。Due to the characterization of high temperature, fast heating-up, higher purity and efficiency, it has become an important technology to prepared bulk heat-resisting materials with nano-structure. The investigation of interface structure and performance of the material prepared by FAPAS will promoted its technical progress and design of products.FAPAS was used to prepare Ti/TiAl joint and functionally gradient materials of TiC-TiB2+Ni/TiAl/Ti. The microstructure and phases of each layer, and the distribution of elements has analyzed by SEM, EDS and XRD。The mechanics performance of synthesize material has tested by friction testing, quenching testing, indentation method and three-point bend testing. The residual stress of bonding interfaces in the cooling process was simulated by ANSYS non-linear finite element method, the law of the distortion, stress and strain of bonding interface was analyzed.From the result of diffusion links material interface structure, the diffusion dissolution layer has been formed of Ti(ss.Al) and (Ti3Al+TiAl) between the interface of Ti-TiAl, and the metal-ceramic TiC-TiB2+Ni got reacted completely to form compact products, and connected with no-gap between the gradient layers, and the elements across the diffusion dissolution layer distribution in grade.It was concluded that the current was the most important factors which determined the connection strength, the metal-ceramic had higher fracture toughness, and the joint interface had higher wear-resistance and shear bond strength. The fracture toughness reached to 9.696±0.42 MPa-m1/2 and the maximum shear bond strength reached to 85.88MPa.The ANSYS result showed that the stress and strain has been caused because of the difference of thermal expansion, the warping has formed in the thickness direction, and the maximum equivalent stress and shear stress located in the transition layer, which becomes the weak region of sample, the equivalent stress of Ti-TiAl joint was 9.24MPa, and the maximum equivalent stress of functionally gradient materials of TiC-TiB2+Ni/TiAl/Ti was 16.9MPa.