Solid-state diffusion bonding (DB) of TiAl alloy and Ti2AlNb alloy was carried out using pure Ti as an interlayer at 1000 °C under 20 MPa for 60–120 min. The effects of bonding times on the interfacial microstructure and mechanical performance of the TiAl/Ti/Ti2AlNb bonded joints at room temperature (RT) were investigated detailly. The results demonstrated that the diffusion layers (DLs) mainly consisted of four characteristic layers, (I) single coarse α2 phase adjacent TiAl alloy, (II) single refined α2 phase at the bonding interface, (III) equiaxed/acicular α2 phase embedded in β phase adjacent Ti2AlNb alloy and (IV) both equiaxed α2 phase and acicular O phase embedded in β phase adjacent Ti2AlNb alloy, respectively. The thickness of the four layers increased with the increasing of the bonding time. The growth of DLs is controlled by diffusion and the reaction rate constant k for region I, II, III and IV are 1.22 × 10−6, 1.27 × 10−6, 2.6 × 10−7 and 7.7 × 10−7 m·s−1/2, respectively. Meanwhile, the interface α2 grain grows up without texture. The maximum tensile strength of 281 MPa was maintained at 1000 °C for 90 min under the pressure of 20 MPa. Consequently, the phase transformation and dynamic recrystallization behavior of the DLs were discussed.

中文翻译：

---

TiAl/Ti2AlNb 纯钛夹层扩散结合接头的界面特性及力学性能

TiAl 合金和 Ti2AlNb 合金的固态扩散键合 (DB) 使用纯 Ti 作为中间层，在 1000 °C 和 20 MPa 下进行 60-120 分钟。详细研究了结合时间对室温下 TiAl/Ti/Ti2AlNb 结合接头界面微观结构和力学性能的影响。结果表明，扩散层（DLs）主要由四个特征层组成，（I）与TiAl合金相邻的单一粗α2相，（II）结合界面处的单一细化α2相，（III）等轴/针状α2相嵌入在β 相邻近 Ti2AlNb 合金和 (IV) 等轴 α2 相和针状 O 相分别嵌入在邻近 Ti2AlNb 合金的 β 相中。四层的厚度随着键合时间的增加而增加。DLs的生长受扩散控制，区域I、II、III和IV的反应速率常数k为1.22×10-6、1.27×10-6、2.6×10-7和7.7×10-7 m·s -1/2，分别。同时，界面α2晶粒长大无织构。在 20 MPa 的压力下，在 1000 °C 下保持 90 分钟的最大拉伸强度为 281 MPa。因此，讨论了 DLs 的相变和动态再结晶行为。