Research of Welding Stress of Field Emission Array Based on ANSYS

The influence of brazing parameters on the equivalent stress of welding field emission array and molybdenum electrode was simulated by ANSYS and the results of simulation were verified by vacuum brazing technique. Simulating results show that when brazing temperature was 850 ℃, it had the minimum equivalent stress. When the cooling rate was 23 ℃/min, the equivalent stress reached the maximum, and then decreased rapidly with increasing cooling rate. During the cooling process, the high temperature zone gradually extended to the silicon substrate, and the temperature distribution was symmetrical along brazing seam, in accompany with high temperature in brazing seam center and low temperature on both sides. Experimental results show that brazed joint was dense and brazing seam was well combined without any defects such as cracks and voids. Collectively, this method may be a viable and cost-effective route for welding the field emission cathode array with molybdenum electrode.