论文标题
氢空位相互作用对ALMGSI合金自然和人工衰老的影响
Influence of hydrogen vacancy interactions on natural and artificial ageing of an AlMgSi alloy
论文作者
论文摘要
通过实验研究了氢对自然和人工衰老过程中Al-MG-SI合金的结构演变的影响。该研究的目的是更好地了解氢与晶体缺陷，尤其是空缺之间的相互作用。实验数据表明，在氢环境中的自然衰老中，硬化反应会延迟。这归因于与较低的移动性相关的多余空缺的恢复较慢。为了确认和量化氢对空位迁移能的影响，在空位浓度恒定的条件下进行人工老化。因此，进行了长期退火处理，以研究氢对棒状沉淀物的变形的影响。使用透射电子显微镜和原子探针断层扫描，证明沉淀体积分数和组成在H2大气下没有变化，但变色的动力学显着降低。这导致延迟软化，与理论估计值很好地吻合。因此，即使在固体溶液中的低浓度氢也会显着影响铝基质中合金元件的迁移率。这是导致空位迁移能量增加的氢相互作用的结果。基于经典的粗化理论，可以证明，对于接近空位浓度的氢气，这种增加约为5％。
The influence of hydrogen on the structural evolutions of an Al-Mg-Si alloy during natural and artificial ageing was investigated experimentally. The aim of the study was a better understanding of interactions between hydrogen and crystalline defects and especially vacancies. Experimental data demonstrate that during natural ageing in hydrogen environment, the hardening response is delayed. This is attributed to a slower recovery of excess vacancies linked to a lower mobility. To confirm and quantify the influence of hydrogen on the vacancy migration energy, artificial ageing was carried out in conditions where the vacancy concentration is constant. Hence, long-time annealing treatments were carried out to investigate the influence of hydrogen on the coarsening of rod-shaped precipitates. Using transmission electron microscopy and atom probe tomography, it was demonstrated that the precipitate volume fraction and composition are unchanged under H2 atmosphere but the coarsening kinetic is significantly reduced. This leads to a delayed softening, in good agreement with theoretical estimates. Thus, even a low concentration of hydrogen in solid solution significantly affects the mobility of alloying elements in the aluminium matrix. This is the result of hydrogen-vacancy interactions that lead to an increase of the vacancy migration energy. Based on classical coarsening theories, it was possible to demonstrate that this increase is of about 5% for a concentration of hydrogen close to the vacancy concentration.
