Abstract

The onset of plastic deformation is an important parameter for an accurate description of the flow curve and the Young’s modulus. Determining the actual physical start of flow is already experimentally challenging for classic sheet metal materials. In addition to the experimental challenge, the onset of flow depends on numerous parameters such as strain rate, temperature and forming history. Non-proportional load paths in particular can significantly influence the onset of flow. Three different materials, a micro-alloyed steel HC340LA, a dual-phase steel CR330Y590-DP and an aluminium alloy AA6016-T4 are investigated in this publication. The physical onset of flow of the materials is determined at three different pre-strain levels as well as without and with a change in the load direction. Temperature-based approaches are used for this purpose. In-situ synchrotron diffraction is used to validate the results obtained. Those results can help to improve existing material models and springback prediction. Such models rely on material parameters that are as accurate as possible.

中文翻译：

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载荷方向变化后屈服开始和杨氏模量的测定

摘要

塑性变形的开始是准确描述流动曲线和杨氏模量的重要参数。对于经典的金属板材来说，确定流动的实际物理开始已经在实验上具有挑战性。除了实验挑战之外，流动的开始还取决于许多参数，例如应变率、温度和成形历史。非比例负载路径尤其会显着影响流动的开始。本出版物研究了三种不同的材料：微合金钢 HC340LA、双相钢 CR330Y590-DP 和铝合金 AA6016-T4。材料的物理流动开始是在三个不同的预应变水平以及负载方向没有变化和有变化的情况下确定的。基于温度的方法用于此目的。原位同步加速器衍射用于验证所获得的结果。这些结果可以帮助改进现有的材料模型和回弹预测。此类模型依赖于尽可能准确的材料参数。