Joining Of Si₃N₄ To Itself And To C_f/SiC Used For Aerial Rudder Joint Design For Simulation Specimen

By designing Yb（or Y）-Si-Al-O-N glass solder to join Si₃N₄ to itself and to C_f/SiC used for aerial rudder to obtain intermediate layer with more in situ generated β-Sialon phase and the amount of glass. A joint of Si₃N₄ ceramic produced by β-Sialon-glass for middle was obtained. Effect of different Si₃N₄ content in solder, different joining parameters and types of rare earth on microstructure and mechanical properies of joint was investigated. Then the mechanism of the interface was researed.The thermal shock resistance and high temperature oxidation resistance is researed. Using ABAQUS finite element simulation software to analyze the distribution of the stress field after welding cooling of the structural model, and to realize the joint design.With the increase of Si₃N₄ content, the wettability of the based material becomes weak, so the weld gradually becomes widened. At the same time with the increase of Si₃N₄ content, The β-Sialon phase gradually increased, and gradually it becomes thick,the tissue looks like fine needle. When pressure is increased, it is possible to reduce the width of the weld, and can reduce holes, cracks and other defects. When the temperature is 1550℃ and pressure is 0.6 MPa, we use the Y-6SN solder to connect Si₃N₄/Si₃N₄ ane obtained a high strength of 217 MPa.When the temperature is 1550 ℃, pressure is 0.6MPa, we use the Yb-8SN solder to connect the silicon nitride ceramic.Then we obtained the maximum bending strength 244 MPa, and when at 1600 ℃, also achieve a high strength of 233 MPa. when connected silicon nitride ceramic and C_f/SiC composites, by use the solder composition of Yb-6SN, we can obtain a maximum joint shear strength 43 MPa.In the thermal shock experiments of Si₃N₄ ceramic connecting samples, we found that with the increase of N content, the thermal shock resistance of the sample changed for the better, using a sample Yb-8SN solder after the end of the experiment ten times thermal shock, tissue samples yet It found significant deficiencies exist; using Yb-6SN solder connections Si₃N₄ ceramic and C_f/SiC composites samples had good thermal shock resistance and oxidation resistance. Using ABAQUS finite element simulation software to simulate different sizes of rudder- like pieces were studied. When the inclined surface groove is 12 degree, welding performance the rudder- like simulation has the minimum residual stress.