Borides are very important in cast TiAl alloys. Among various morphologies and structures, the long curve ribbon borides are harmful to mechanical properties and need to be avoided or refined. The knowledge on curve ribbon is relatively less than fine boride particles. In the present work, a long ribbon with blocky borides at both ends is studied by SEM, HRTEM， and STEM-EDS method. The ribbon consists of nanoflakes of 4 boride structures and a B2 layer. The blocky boride is Ti₃B₄ with a D7_b structure. The ribbon contains flakes with the structures of D7_b, B27, B_f, C32, and B2. The block is adhesive to the ribbon by a B2 layer with a width of several nanometers. Mn is found to segregate to B2/borides interfaces inside the ribbon. Nb is rich in borides but poor in the B2 phase.

硼化物在铸造 TiAl 合金中非常重要。在各种形貌和结构中，长曲线带状硼化物对力学性能有害，需要避免或细化。曲线带的知识相对小于细硼化物颗粒。在目前的工作中，通过SEM、HRTEM和STEM-EDS方法研究了两端具有块状硼化物的长条带。条带由 4 种硼化物结构的纳米薄片和 B2 层组成。块状硼化物是具有 D7 _b结构的Ti ₃ B ₄。色带包含具有 D7 _b , B27, B _f结构的薄片、C32 和 B2。该块通过宽度为几纳米的 B2 层粘合到带上。发现 Mn 偏析到带内的 B2/硼化物界面。Nb 富含硼化物，但缺乏 B2 相。