To overcome the strength-plasticity trade-off in the structural titanium alloys, a novel metastable β titanium alloy Ti-5Mo-4Cr-1V-1Zr (Ti-5411) with high strength and high plasticity was designed by the -electrons theory, average electron-to-atom ratio () and atomic radius difference () theory. Combined in-situ scanning electron microscope (SEM) and electron backscatter diffraction (EBSD), the deformation mechanisms of the novel Ti-5411 metastable β titanium alloy were systematically investigated. The results show that the Ti-5411 alloy exhibits excellent yield strength (∼689 MPa), tensile strength (∼930 MPa) and total elongation (∼39%). The in-situ tension indicates that slip activities, crystal rotation, stress induced martensite (SIM) α″ transformation and {332}<113> deformation twin are the major deformation mechanisms of Ti-5411 alloy. Besides, with the increase of strain degree (0–0.5 mm displacement), deformation twins increase, widen and interlace. At 0.35 mm tensile displacement, the orientation of the β grains rotates ∼6.65° to accommodate the increased macrostrain. Additionally, martensite α″ also assists the nucleation of twins. Some {332}<113> twins grow and merge by consuming martensite α″ during deformation, and the residual martensite α″ remains in the merged twins.

中文翻译：

---

新型Ti-5Mo-4Cr-1V-1Zr亚稳β钛合金的原位变形机制


为了克服结构钛合金的强度-塑性权衡问题，利用电子理论，平均设计了一种具有高强度和高塑性的新型亚稳态β钛合金Ti-5Mo-4Cr-1V-1Zr（Ti-5411）电子原子比（）和原子半径差（）理论。结合原位扫描电子显微镜（SEM）和电子背散射衍射（EBSD），系统研究了新型Ti-5411亚稳β钛合金的变形机制。结果表明，Ti-5411 合金具有优异的屈服强度（~689 MPa）、抗拉强度（~930 MPa）和总伸长率（~39%）。原位张力表明滑移活动、晶体旋转、应力诱导马氏体（SIM）α”相变和{332}<113>变形孪晶是Ti-5411合金的主要变形机制。此外，随着应变程度（0~0.5 mm位移）的增加，变形孪晶增多、变宽、交错。在 0.35 mm 拉伸位移下，β 晶粒的方向旋转约 6.65° 以适应增加的宏观应变。此外，马氏体α”也有助于孪晶的形核。一些{332}<113>孪晶在变形过程中通过消耗马氏体α”而生长并合并，而残余马氏体α”保留在合并孪晶中。