Chen J H, Costan E, van Huis M A, Xu Q, Zandbergen H W
Netherlands Institute for Metals Research and Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, Netherlands.
Science. 2006 Apr 21;312(5772):416-9. doi: 10.1126/science.1124199.
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 Si2 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.
原子分辨率电子显微镜显示，AlMgSi合金的硬化纳米析出物中存在柱状硅双柱，其结构和成分各不相同。退火后，Si2柱为纳米颗粒在成分、结构和形态上的演变提供了骨架。我们发现，它们最初是微小的核，成分接近Mg2Si2Al7，与铝基体的错配最小。随后，它们伴随着成分变化进行一维生长，变成细长颗粒。在向最终的Mg5Si6颗粒演变的过程中，成分变化伴随着特征性的结构变化。我们的研究解释了这些合金成为优秀汽车材料的纳米层面原因。
