This study investigated the high-temperature microstructure stability of TiAl alloys fabricated by electron beam smelting (EBS) to understand the microstructural evolution of TiAl alloys that were fabricated by selective electron beam melting (SEBM) by comparing the microstructure of EBS- and SEBM-produced TiAl alloy samples. The results showed that with an increase in annealing temperature from 1050 °C to 1250 °C, the degradation of the (α₂/γ) lamellar colony increased. When the annealing temperature was 1050 °C, ellipsoidal B2 precipitates occurred along the primary α₂ lamellae and distributed uniformly within lamellar colonies. The microstructure transformed into (γ/B2) laths when the annealing temperature was 1250 °C. The effect of microstructure and constituent phase on the fracture toughness was investigated for EBS- and SEBM-produced TiAl alloy by observing the fracture path profiles. The EBS-produced TiAl alloy that was heat-treated at 1050 °C for 0.5 h showed the most excellent fracture toughness. The SEBM-fabricated TiAl alloy exhibited the worst fracture toughness due to the fine grain size, degraded lamellar colony, and coarsening γ lath. Finally, the toughening mechanisms for the different microstructures were discussed in detail.

本实验研究的TiAl合金的高温稳定性的微结构制造的通过电子束熔炼（EBS）要明白，通过比较EBS-和的微结构制造通过选择性电子束熔化（SEBM）的TiAl合金的组织演变SEBM产TiAl金属合金样品。结果表明，与在退火温度至1250℃，（α降解的增加，从1050℃ ₂ /γ）层状菌落增加。当退火温度为1050℃，椭圆形的析出物B2沿着初级α发生₂薄片和均匀分布的薄片状集落内。显微组织转化为（γ/ B2）板条当退火温度为1250℃。通过观察断裂路径轮廓，研究了微观结构和组成相对 EBS 和 SEBM 生产的 TiAl 合金断裂韧性的影响。该热处理在1050的EBS-产生的TiAl合金℃下0.5小时显示出最优异的断裂韧性。所述SEBM制造的TiAl金属合金所表现出的最坏断裂韧性由于晶粒细小，退化层状菌落，和粗化γ板条。最后，对于不同的微结构的增韧机制进行了详细讨论。