Abstract Kinematic hardening is incorporated into a nanoscale model for 6000 series aluminium alloys consisting of three sub-models describing in turn precipitation of hardening particles, yield strength and work hardening. The kinematic hardening model assumes that the backstress is caused by an unrelaxed plastic strain around non-shearable particles which is defined by an evolution equation. Compression-tension tests are performed on a cast and homogenized AA6063 aluminium alloy in tempers T6 (peak strength), T7 (overaged) and O (annealed). These tempers have different amounts of non-shearable hardening precipitates and thus exhibit various levels of kinematic hardening. The pre-compression is varied between 0.5% and 6% strain, after which the specimen is stretched to fracture. The grain structure, the constituent particles and the precipitate structure of the three tempers of the alloy are characterized by means of optical microscopy and scanning and transmission electron microscopy. The alloy displays marked kinematic hardening in all three tempers, whereas hardening stagnation is observed for tempers T7 and O. The proposed model captures the stress-strain response during strain reversal by means of the backstress and the storage and annihilation of geometrically necessary dislocations at the non-shearable particles.

中文翻译：

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6000 系列铝合金各向同性硬化和运动硬化相结合的纳米级建模

摘要 6000 系列铝合金的运动硬化被纳入一个纳米级模型，该模型由三个子模型组成，依次描述硬化颗粒的析出、屈服强度和加工硬化。运动硬化模型假设背应力是由不可剪切粒子周围的未松弛塑性应变引起的，该应变由演化方程定义。在 T6（峰值强度）、T7（过时效）和 O（退火）状态下对铸造和均质化的 AA6063 铝合金进行压缩-拉伸试验。这些回火具有不同数量的不可剪切硬化沉淀物，因此表现出不同程度的运动硬化。预压缩在 0.5% 和 6% 应变之间变化，之后试样被拉伸至断裂。晶粒结构，通过光学显微镜和扫描透射电子显微镜对合金的三种状态的组成颗粒和析出物结构进行表征。该合金在所有三种状态下都显示出明显的运动硬化，而在 T7 和 O 状态下观察到硬化停滞。 所提出的模型通过背应力和几何必要位错的存储和消除来捕获应变反转期间的应力应变响应。不可剪切的颗粒。