Atomic pillar-based nanoprecipitates strengthen AlMgSi alloys
Atomic pillar-based nanoprecipitates strengthen AlMgSi alloys
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DOI：
10.1126/science.1124199
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发表时间：
2006-04-21
期刊：
影响因子：
56.9
通讯作者：
Zandbergen, HW
中科院分区：
文献类型：
--
作者：
Chen, JH;Costan, E;Zandbergen, HW
原子分辨电子显微镜研究表明，在AlMgSi合金的硬化纳米沉淀物中存在柱状硅双柱，其结构和成分各不相同。在退火时，Si柱为纳米颗粒提供骨架以在组成、结构和形态上演变。我们表明，他们开始作为微小的核心与组成接近Mg2Si2Al7和最小的错配与铝基体。它们随后经历与成分变化相关的一维生长，成为细长颗粒。在向最终Mg5Si6颗粒的演变过程中，成分变化伴随着特征结构变化。我们的研究解释了合金成为优秀汽车材料的纳米原因。
Atomic-resolution electron microscopy reveals that pillarlike silicon double columns exist in the hardening nanoprecipitates of AlMgSi alloys, which vary in structure and composition. Upon annealing, the Si, pillars provide the skeleton for the nanoparticles to evolve in composition, structure, and morphology. We show that they begin as tiny nuclei with a composition close to Mg2Si2Al7 and a minimal mismatch with the aluminum matrix. They subsequently undergo a one-dimensional growth in association with compositional change, becoming elongated particles. During the evolution toward the final Mg5Si6 particles, the compositional change is accompanied by a characteristic structural change. Our study explains the nanoscopic reasons that the alloys make excellent automotive materials.