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Modeling the Age-Hardening Process of Aluminum Alloys Containing the Prolate/Oblate Shape Precipitates
Metals and Materials International ( IF 3.5 ) Pub Date : 2020-01-02 , DOI: 10.1007/s12540-019-00579-7
Nozar Anjabin

Abstract

Non-spherical precipitates are the main strengthening source of the age-hardenable aluminum alloys. In the majority of the precipitation hardening models presented so far, the simple spherical shape has been assumed. Moreover, the models which considered the actual shape of the precipitates, are derived based on the simple assumption of steady-state diffusion problem solutions. In the present study, the classical Kampmann and Wagner numerical model of spherical precipitates is extended to model the kinetics of spheroidal shape precipitates evolution during the aging treatment of Al alloys. To do so, a new rate law is proposed using a similarity solution of the transient diffusion problem around the spheroidal precipitates, with different aspect ratios, and moving boundaries. Moreover, a modified age-hardening model which considered the effects of precipitate shape, size and volume fraction, is used to predict the variation of the alloy hardness during the aging process. The accuracy of the proposed model is shown by comparing the predicted features of precipitates, and hardness evolution with the published experimental data. Also, the validity of the existing approximate solutions for the aging problem is discussed.

Graphic Abstract



中文翻译:

建模含有长方体/长方体形沉淀物的铝合金的时效强化过程

抽象的

非球形沉淀是时效硬化铝合金的主要强化来源。到目前为止,在给出的大多数沉淀硬化模型中,都假定为简单的球形。此外,基于稳态扩散问题解决方案的简单假设,得出了考虑沉淀物实际形状的模型。在本研究中,扩展了球形沉淀物的经典Kampmann和Wagner数值模型,以模拟铝合金时效处理过程中球形沉淀物的演化动力学。为此,提出了一种新的速率定律,该方法使用了球状沉淀物周围具有不同长宽比和移动边界的瞬态扩散问题的相似解。而且,修改后的时效硬化模型考虑了析出物形状,尺寸和体积分数的影响,用于预测时效过程中合金硬度的变化。通过比较析出物的预测特征和硬度演变与已发布的实验数据,可以证明所提出模型的准确性。此外,还讨论了针对老化问题的现有近似解的有效性。

图形摘要

更新日期:2020-01-02
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