【摘要】 详细研究了直热式单晶六硼化镧（LaB₆）阴极在电子束焊机中的应用。在实验室原有电子束焊机基础上，设计增加了束斑直径测量装置并进行了电子枪发射能力、阴极寿命及焊缝成形测试。结果显示，与钨（W）阴极相比，LaB₆阴极不仅束斑直径小、电子束能量集中、而且寿命更长、焊缝深宽比更大。5 mA发射束流下，LaB₆阴极束斑直径为W阴极的1/5；在焊接功率3.6 kW、速度4 mm/s的条件下，LaB₆阴极能轻松焊透20 mm不锈钢板，焊缝深宽比是W阴极的2倍；此外，LaB₆阴极寿命大于100 h，约为W阴极的10倍。本研究结合实验数据，证明了LaB₆阴极相对于W阴极具有显著优势，为LaB₆阴极在电子束焊接领域的应用提供了重要参考价值。更多还原

【Abstract】 The application of directly heated single crystal lanthanum hexaboride（LaB₆）cathodes in electron beam welding machines is deeply studied in this paper. Based on a original laboratory electron beam welding machine, a beam spot diameter measurement device was designed, and tests on the emission capacity of the electron gun, cathode life, and weld formation were carried out. The results show that compared with tungsten（W） cathode, the LaB₆ cathode not only has a smaller beam spot diameter and more concentrated electron beam energy, but also has a longer lifespan anda larger depth-to-width ratio of the weld seam. At an emission beam current of 5 mA, the beam spot diameter of the LaB₆ cathode is only 1/5 that of the W cathode. Under the conditions of a welding power of 3.6 kW and a speed of 4 mm/s, the LaB₆ cathode can easily penetrate a 20 mm thick stainless-steel plate, and the depth-to-width ratio of the weld is 2 times that of the W cathode. In addition, the lifespan of the LaB₆ cathode is greater than 100 h, approximately 10 times that of the W cathode. This studythat proves that the LaB₆ cathode has significant advantages over the W cathode, providing significant reference value for the application of LaB₆ cathodes in the field of electron beam welding.更多还原