Oxygen is always a constituent in “real” titanium alloys including titanium alloy powders used for powder-based additive manufacturing (AM). In addition, oxygen uptake during powder handling and printing is hard to control and, hence, it is important to understand and predict how oxygen is affecting the microstructure. Therefore, oxygen is included in the evaluation of the thermodynamic properties of the titanium-vanadium system employing the CALculation of PHAse Diagrams method and a complete model of the O-Ti-V system is presented. The β-transus temperature is calculated to increase with increasing oxygen content whereas the extension of the α-Ti phase field into the binary is calculated to decrease, which explains the low vanadium solubilities measured in some experimental works. In addition, the critical temperature of the metastable miscibility gap of the β-phase is calculated to increase to above room temperature when oxygen is added. The effects of oxygen additions on phase fractions, martensite and ω formation temperatures are discussed, along with the impacts these changes may have on AM of titanium alloys.

中文翻译：

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氧对 Ti-V 体系中相平衡的影响：对 Ti 合金 AM 加工的影响

氧气始终是“真正的”钛合金的成分，包括用于基于粉末的增材制造 (AM) 的钛合金粉末。此外，粉末处理和印刷过程中的氧气吸收量难以控制，因此，了解和预测氧气如何影响微观结构非常重要。因此，在使用 PHA 酶图计算方法评估钛-钒系统的热力学性能时将氧气包括在内，并提供了 O-Ti-V 系统的完整模型。β-转变温度被计算为随着氧含量的增加而增加，而 α-Ti 相场向二元相的扩展被计算为减少，这解释了在一些实验工作中测量的低钒溶解度。此外，当加入氧气时，β相的亚稳态混相间隙的临界温度经计算增加到室温以上。讨论了氧添加对相分数、马氏体和 ω 形成温度的影响，以及这些变化可能对钛合金增材制造的影响。