Evolution and Manipulation of Interstitial Oxygen Configuration in Titanium—A Review

Oxygen has been regarded as a detrimental impurity in titanium alloys, as it triggers embrittlement and compromises ductility. Recent research advancements, however, have revolutionized this perception, revealing oxygen as a powerful microstructural architect capable of mediating phase transformations and deformation mechanisms to achieve strength-ductility combinations. This review systematically summarizes the pivotal roles of oxygen across various phases, including α, β, α', α″, ω, and face-centered cubic (FCC) phases. The underlying strengthening mechanisms and the oxygen embrittlement mechanisms were further analyzed, covering the strengthening theoretical models, interfacial segregation behaviors, and oxygen shuffling mechanism. These mechanistic insights are essential for understanding the evolution of dislocation configurations, twinning behaviors, and phase transformation dynamics. To harness oxygen's strengthening potential while mitigating its adverse effects, potential innovative strategies, including compositional, microstructural, and process design approaches, are proposed, which span from the atom-scale to the micro-scale. By integrating multiscale computational simulations, advanced in situ characterization, and the challenge of controlling oxygen uptake, this work provides a comprehensive framework for the intelligent design of next-generation oxygen-containing titanium alloys with exceptional mechanical properties.