基于ANSYS的场发射阵列阴极焊接应力研究

该文基于ANSYS平台模拟了场发射阵列阴极与钼电极钎焊工艺参数对钎焊层等效应力的影响，并根据仿真结果进行了实验验证。仿真结果表明，当钎焊温度为850 ℃时，最大等效应力最小；当降温速率为23 ℃/min时，最大等效应力最大，之后随降温速度的增加而迅速减小；在降温过程中，高温区逐渐向硅基底扩展，温度沿焊缝方向呈对称分布，焊缝中心温度高，两边温度低。测试结果表明，钎焊接头组织致密，焊缝结合良好，没有裂纹和空洞等缺陷，且钎料对硅基底的影响很小。这是一种可行的、低成本的实现硅基场发射阵列阴极焊接的有效方法。

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.