A constitutive model was developed to predict the high temperature sub-transus flow behavior of a metastable β Ti-10V-2Fe-3Al alloy, and its applicability for industrial scale forging process has been evaluated using a finite element simulation. Cylindrical samples extracted from a cogged billet of the alloy after β recrystallisation treatment were subjected to hot compression tests at sub-transus temperatures ranging from 720 °C to 780 °C with an increment of 15 °C under varying strain rates from 0.025 to 0.2 s⁻¹. The sub-transus flow curves of the alloy exhibited work hardening followed by dynamic recovery and flow softening beyond the strain equivalent to peak stress. Formation of low angle grain boundaries within the prior β grains and dynamic recrystallisation of β phase were observed to contribute to the flow softening. A constitutive model based on Estrin Mecking and Avrami methods was developed with minimised number of material constants, using the data derived from the hot compression tests. The model was successfully verified using the deformation behaviour measured for the alloy in the region of interest. The constitutive model was implemented into a finite element package as a user subroutine to predict the flow behaviour of industrial scale billets during open die hot forging processes and validated using experimental trials. A fairly good predictive capability with more than 95% convergence for open die forging was achieved, confirming the suitability of the material model developed for predicting sub-transus forgeability of the Ti-10V-2Fe-3Al alloy during industrial scale forging.

开发了一个本构模型来预测亚稳态 β Ti-10V-2Fe-3Al 合金的高温亚转变流动行为，并使用有限元模拟评估了其在工业规模锻造过程中的适用性。在 720 °C 至 780 °C 的亚转变温度下，在 0.025 至 0.2 秒的不同应变速率下，从带齿的合金坯料中提取的圆柱形样品进行热压缩试验，增量为 15 °C。⁻¹. 合金的亚转变流动曲线表现出加工硬化，随后是动态恢复和流动软化，超过等效于峰值应力的应变。观察到在先前的 β 晶粒内形成小角度晶界和 β 相的动态再结晶有助于流动软化。使用来自热压缩测试的数据，开发了一个基于 Estrin Mecking 和 Avrami 方法的本构模型，其中材料常数数量最少。使用对感兴趣区域中的合金测量的变形行为成功地验证了该模型。本构模型作为用户子程序实施到有限元包中，以预测工业规模钢坯在开模热锻过程中的流动行为，并使用实验进行验证。