Intermetallic γ-TiAl alloy has been considered as a promising structural material for high temperature use, owing to their advantages such as low density, high creep strength and good toughness. However, due to its intrinsic brittleness, γ-TiAl alloy could not accommodate the high thermal stress generated by fast cooling during laser-based additive manufacturing (LAM) process, resulting in cracking and distortion. To surmount the roadblock of low processability associated with γ-TiAl alloy, grain refinement technology was integrated to LAM. In the present work, LaB₆ nanoparticles were identified and experimentally verified, for the first time, as an effective inoculant for LAMed γ-TiAl alloy. The results showed that the grain size of the as-printed alloy drastically decreased from 39.81 ± 9.12 µm to 1.5 ± 2.07 µm through 0.5 wt% LaB₆ addition. Accordingly, the microstructural morphology transformed from coarse near-lamellar colonies into equiaxed and fine grains. The LaB₆ inoculation treatment not only led to the fabrication of crack-free alloy but concurrently increases in compressive yield strength, ultimate strength and strain to fracture by 29%, 12.4% and 61.9%, respectively. Such an enhanced performance is comparable with or even better than the γ-TiAl alloys produced using conventional processing techniques.

金属间γ-TiAl合金由于具有低密度、高蠕变强度和良好的韧性等优点，被认为是一种很有前途的高温结构材料。然而，γ-TiAl合金由于其固有的脆性，无法适应激光增材制造（LAM）过程中快速冷却产生的高热应力，导致开裂和变形。为了克服γ-TiAl合金加工性低的障碍，将晶粒细化技术集成到LAM中。在目前的工作中，LaB ₆纳米粒子首次被鉴定和实验验证，作为 LAMed γ-TiAl 合金的有效孕育剂。结果表明，通过添加 0.5 wt% 的 LaB _6，打印后合金的晶粒尺寸从 39.81 ± 9.12 µm 急剧下降到 1.5 ± 2.07 µm 。因此，微观结构形态从粗糙的近层状菌落转变为等轴细晶粒。LaB ₆孕育处理不仅导致制造无裂纹合金，而且同时将压缩屈服强度、极限强度和断裂应变分别提高了29%、12.4%和61.9%。这种增强的性能与使用传统加工技术生产的 γ-TiAl 合金相当甚至更好。