Abstract

An effort has been made to establish a relation between Zener–Hollomon parameter, flow stress and dynamic recrystallization (DRX). In this context, the plastic flow behavior of Ti + Nb stabilized interstitial free (IF) steel was investigated in a temperature range of 650–1100 °C and at constant true strain rates in the range 10⁻³–10 s⁻¹, to a total true strain of 0.7. The flow stress curves can be categorized into two distinct types, i.e. with/without the presence of steady-state flow following peak stress behavior. A novel constitutive model comprising the strain effect on the activation energy of DRX and other material constants has been established to predict the constitutive flow behavior of the IF steel in both α and γ phase regions, separately. Predicted flow stress seems to correlate well with the experimental data both in γ and α phase regions with a high correlation coefficient (0.982 and 0.936, respectively) and low average absolute relative error (7 and 11%, respectively) showing excellent fitting. A detailed analysis of the flow stress, activation energy of DRX and stress exponent in accord with the modelled equations suggests that dislocation glide controlled by dislocation climb is the dominant mechanism for the DRX, as confirmed by the transmission electron microscopy analysis.

Graphic Abstract

中文翻译：

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Ti + Nb稳定间隙自由钢的热变形特征和应变相关本构流应力模型

摘要

已努力建立齐纳-所罗门参数，流动应力和动态重结晶（DRX）之间的关系。在此背景下，研究了Ti + Nb稳定的无间隙（IF）钢在650–1100°C的温度范围内以及在10 ^-3 –10 s ^-1的恒定真实应变速率下的塑性流动行为，直至总真实应变为0.7。流动应力曲线可分为两种不同的类型，即在峰值应力行为之后是否存在稳态流动。建立了包含应变效应对DRX活化能和其他材料常数的新颖本构模型，以预测IF钢在α和γ中的本构流动行为相区域，分别。预测的流应力似乎在γ和α相区域均与实验数据很好地相关，具有高的相关系数（分别为0.982和0.936）和较低的平均绝对相对误差（分别为7％和11％），显示出极好的拟合度。根据模型方程对流动应力，DRX的活化能和应力指数进行的详细分析表明，由位错爬升控制的位错滑移是DRX的主要机理，这已由透射电子显微镜分析证实。

图形摘要