Welded joints of molybdenum (Mo) and Mo alloy have high brittleness and low strength, which seriously limit its application as structural materials. In this study, Nitrogen (N) is used to strengthen the fusion zone (FZ) in the Mo laser beam welding joints and N is added into the FZ during a laser gas alloying process. The XPS and SEM confirm that many Mo₂N phase were distributed on the surface of the grain boundary. The EBSD results indicate that Mo₂N, which can be distributed at the grain boundary and inside the grain, tends to distribute more at the grain boundary. The tensile strength of joint by laser gas alloying is up to 382 MPa. Mo₂N in the FZ plays the role of second phase strengthening. The presence of Mo₂N in the FZ facilitates the second phase strengthening, allowing the application of Mo as a structural material.

钼和钼合金的焊接接头脆性高，强度低，严重限制了其作为结构材料的应用。在这项研究中，氮（N）用于增强Mo激光束焊接接头中的熔合区（FZ），并且在激光气体合金化过程中将N添加到FZ中。XPS和SEM证实了许多Mo ₂ N相分布在晶界表面上。EBSD结果表明，Mo ₂ N可以分布在晶界和晶粒内部，而倾向于分布在晶界。激光气体合金化的接头抗拉强度高达382 MPa。FZ中的Mo ₂ N起到第二相强化的作用。Mo ₂的存在FZ中的N有助于第二相强化，从而允许使用Mo作为结构材料。