Tensile deformation and damage evolution of a metastable β titanium alloy (Ti–5Cr–4Al–4Zr–3Mo–2W–0.8Fe) with lamellar microstructure are studied by in-situ tensile test under scanning electron microscopy. In the tensile process, the main deformation modes include the dislocation slip, phase interface shear and grain boundary shear, and the geometrical orientation of α lamellae determines the activation of different slip systems and whether the interface shear is involved in deformation. The α lamellae may kink and even fragment under severe deformation. Slip transfer is prone to occur between α lamella and β interlayer that satisfy the Burgers orientation relationship, and the slip lines will deflect and bifurcate as more slip systems are activated and grains rotate. Due to the localized stress concentration and inhomogeneous deformation, the grain boundaries, phase interfaces, tips of β interlayers, junctions of colonies composed of α lamellae and shear bands are all the positions where are easy to generate microvoids. The crack propagates along a zigzag path on account of the synergistic reaction mechanism of critical resolved shear stress, activated slip system, shear band and grain boundary shear, resulting in an intergranular and transgranular mixed fracture mode.

通过扫描电子显微镜下的原位拉伸试验研究了具有层状组织的亚稳态β钛合金（Ti-5Cr-4Al-4Zr-3Mo-2W-0.8Fe）的拉伸变形和损伤演变。在拉伸过程中，主要的变形模式包括位错滑移、相界面剪切和晶​​界剪切，α片晶的几何取向决定了不同滑移系统的激活以及界面剪切是否参与变形。α 薄片在剧烈变形下可能扭结甚至断裂。满足 Burgers 取向关系的 α 片层和 β 夹层之间容易发生滑移传递，随着更多滑移系统被激活和晶粒旋转，滑移线将发生偏转和分叉。由于局部应力集中和不均匀变形，晶界、相界面、β 夹层尖端、α 片层组成的菌落连接处和剪切带都是容易产生微孔洞的位置。由于临界分辨剪切应力、活化滑移系统、剪切带和晶界剪切的协同反应机制，裂纹沿锯齿形路径扩展，导致晶间和穿晶混合断裂模式。