Abstract In this work, quasi-in situ tensile unloading and electron backscatter diffraction (EBSD)-based slip trace analysis were applied to study the room-temperature deformation behaviour of Ti 22Al 25Nb alloys with three different microstructures and the plastic deformation mechanism of the B2, α2, and O phases. In addition, the interaction model of the three phases was presented. The results showed obvious B2 slip deformation in the necking region of the B2+α2 microstructure and the B2 texture+α2 samples. The cracks expanded along the regions with low grain boundary density, and the fracture mode was transgranular fracture. The B2 texture improved the harmony and uniformity of the slip deformation between different grains, obviously improving ductility. Owing to the obstruction of the O phase to the B2 phase slip, the B2+O+α2 sample generated an obvious deformation strengthening effect, had no necking phenomenon, and it was also transgranular fracture. The B2 phase slip deformation mode included single system, double system, tri-system, and cross slips. The B2 phase induced a small number of the α2 phases to experience basal slip ((0001) [11–20]) and cracking. The O phase had two deformation modes: (001) plane slip and twin that had (021) as a twinning plane. Two of the 24 slip systems of the B2 phase {110} and {112} can induce an O phase (001) plane slip, 12 systems whose slip direction formed a 54.7° angle with the (001) plane can induce an O phase twin, and other 10 systems cannot induce O phase deformation.

中文翻译：

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Ti-22Al-25Nb合金室温塑性变形机制及B2、α2、O相相互作用

摘要 本工作采用准原位拉伸卸载和电子背散射衍射 (EBSD) 滑移迹线分析方法研究了三种不同显微组织 Ti 22Al 25Nb 合金的室温变形行为和 B2 合金的塑性变形机制。 、α2 和 O 相。此外，还提出了三个阶段的交互模型。结果表明，B2+α2显微组织和B2织构+α2试样的颈缩区有明显的B2滑移变形。裂纹沿晶界密度低的区域扩展，断裂方式为穿晶断裂。B2织构提高了不同晶粒间滑移变形的协调性和均匀性，显着提高了延性。由于 O 相阻碍 B2 相滑移，B2+O+α2试样产生明显的变形强化作用，无颈缩现象，也是穿晶断裂。B2相滑移变形模式包括单系、双系、三系和交叉滑移。B2 相诱导少量 α2 相经历基底滑移 ((0001) [11-20]) 和开裂。O相有两种变形模式：（001）平面滑移和以（021）为孪晶面的孪晶。B2相{110}和{112}的24个滑移系统中的两个可以诱导O相（001）面滑移，滑移方向与（001）面形成54.7°角的12个系统可以诱导O相孪晶，而其他 10 个系统不能引起 O 相变形。B2相滑移变形模式包括单系、双系、三系和交叉滑移。B2 相诱导少量 α2 相经历基底滑移 ((0001) [11-20]) 和开裂。O相有两种变形模式：（001）平面滑移和以（021）为孪晶面的孪晶。B2相{110}和{112}的24个滑移系统中的两个可以诱导O相（001）面滑移，滑移方向与（001）面形成54.7°角的12个系统可以诱导O相孪晶，而其他 10 个系统不能引起 O 相变形。B2相滑移变形模式包括单系、双系、三系和交叉滑移。B2 相诱导少量 α2 相经历基底滑移 ((0001) [11-20]) 和开裂。O相有两种变形模式：（001）平面滑移和以（021）为孪晶面的孪晶。B2相{110}和{112}的24个滑移系统中的两个可以诱导O相（001）面滑移，滑移方向与（001）面形成54.7°角的12个系统可以诱导O相孪晶，而其他 10 个系统不能引起 O 相变形。