Abstract Laser-additive welding using TiB2 powder with different weight fractions and sizes was applied to join a Ti-22Al-25Nb (at.%) alloy. In the heat-affected zone (HAZ), the O→B2 phase transformation led to the formation of a single B2 phase region. In the case of the joints produced using the TiB2 powder with a particle size of 4–10 μm, the fusion zone was composed of the B2 and intergranular TiB phases. In the case of the joints produced using the 40–100-μm TiB2 powder, the B2 and intergranular TiB phases and unmelted TiB2 particles were formed in the fusion zone as the TiB2 weight fraction was higher than 6.0 wt.%. When the laser-additive welding was carried out using 3.1 wt.% of the 4–10-μm TiB2 powder, the fusion zone grain size decreased to 63.1 μm, and the low-angle grain boundary (

中文翻译：

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添加TiB2粉末改善激光焊接Ti-22Al-25Nb接头的显微组织和高温脆性

摘要 使用不同重量分数和尺寸的 TiB2 粉末进行激光增材焊接以连接 Ti-22Al-25Nb (at.%) 合金。在热影响区 (HAZ)，O→B2 相变导致形成单个 B2 相区域。在使用粒径为 4-10 μm 的 TiB2 粉末生产的接头的情况下，熔合区由 B2 和晶间 TiB 相组成。在使用 40-100-μm TiB2 粉末生产的接头的情况下，B2 和晶间 TiB 相以及未熔化的 TiB2 颗粒在熔合区形成，因为 TiB2 的重量分数高于 6.0 wt.%。当使用 3.1 wt.% 的 4-10-μm TiB2 粉末进行激光增材焊接时，熔合区晶粒尺寸减小至 63.1 μm，小角度晶界（