A Phenomenological Mechanical Material Model for Precipitation Hardening Aluminium Alloys
A Phenomenological Mechanical Material Model for Precipitation Hardening Aluminium Alloys
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DOI：
10.3390/met9111165
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发表时间：
2019-11-01
期刊：
影响因子：
2.9
通讯作者：
Kessler, Olaf
中科院分区：
文献类型：
--
作者：
Froeck, Hannes;Kappis, Lukas Vincent;Kessler, Olaf
时效硬化铝合金通过形成析出物获得强度。这种沉淀硬化状态通常是短期热处理的初始条件，例如焊接过程或局部激光热处理以生产定制的热处理型材(THTP)。在这些热处理过程中，根据最高温度，强度增加的析出物被溶解，材料在这些区域软化。根据温度路径的不同，在相同温度下加热和冷却时的机械性能也会有所不同。为了模拟这一行为，根据溶解特性建立了唯象材料模型，并绘制了依赖于当前温度和最高温度的实验流动曲线。用量热法分析了其溶出特性。通过热机械分析，记录了不同温度和峰值温度下的力学性能。利用有限元程序中常用的相变方程，建立了力学性能随热处理工艺参数变化的唯象模型。该材料模型是在有限元软件LS-DYNA(Livermore Software Technology Corporation)中对6060 T4铝合金建立的。
Age hardening aluminium alloys obtain their strength by forming precipitates. This precipitation-hardened state is often the initial condition for short-term heat treatments, like welding processes or local laser heat treatment to produce tailored heat-treated profiles (THTP). During these heat treatments, the strength-increasing precipitates are dissolved depending on the maximum temperature and the material is softened in these areas. Depending on the temperature path, the mechanical properties differ between heating and cooling at the same temperature. To model this behavior, a phenomenological material model was developed based on the dissolution characteristics and experimental flow curves were developed depending on the current temperature and the maximum temperature. The dissolution characteristics were analyzed by calorimetry. The mechanical properties at different temperatures and peak temperatures were recorded by thermomechanical analysis. The usual phase transformation equations in the Finite Element Method (FEM) code, which were developed for phase transformation in steels, were used to develop a phenomenological model for the mechanical properties as a function of the relevant heat treatment parameters. This material model was implemented for aluminium alloy 6060 T4 in the finite element software LS-DYNA (Livermore Software Technology Corporation).