铸态钛合金热变形行为及其弹黏塑性本构模型

Hot Deformation Behavior and Elastic-viscoplastic Constitutive Model of As-Cast Titanium Alloy

  • 摘要: 本研究开展了铸态Ti-6554合金在变形温度为950~1 150 ℃、应变速率为0.001~10 s-1下的热压缩试验,并依据流动曲线,基于有限变形理论,建立了精确描述钛合金热变形的弹黏塑性本构模型。流动曲线中所显示的钛合金在热变形过程中的流动软化、稳态流动、加工硬化、不连续屈服与绝热温升等流动行为是使用应变修正的一维线性回归Arrhenius方程捕获的。此外,开发了该本构模型的有限元子程序,模拟了不同应变速率和变形温度下样品的热压缩过程,试验与预测结果吻合较好,证明所建立的本构模型能够精确捕捉钛合金热变形时的复杂流动特征。

     

    Abstract: In this work, the hot compression experiments of as-cast Ti-6554 alloy are carried out with the temperature range of 950-1 150 ℃ and the strain rate range of 0.001-10 s-1. An elastic-viscoplastic constitutive model to describe the hot deformation of titanium alloy is established based on the theory of finite deformation and flow curve. The hot deformation behaviors of titanium alloy in the flow curve such as flow softening, steady flow, work hardening, discontinuous yield and adiabatic temperature rise are captured using a one-dimensional linear regression Arrhenius equation with strain corrected. In addition, the finite element subroutine of the constitutive model is developed to simulate the hot compression process of samples at different strain rates and temperatures. The experimental results are in good agreement with the predicted ones, proving that the established constitutive model can accurately capture the complex flow characteristics of titanium alloy during hot deformation.

     

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