Microstructure and Mechanical Properties of an Al-Mo in situ Nanocomposite Produced by Friction Stir Processing

摘要

In this work, friction stir processing (FSP) was applied to produce aluminum based nanocomposites from powder mixtures of Al-Mo. This technique combines the hot working nature of FSP and the exothermic reaction between Al and Mo. Fully dense Al-matrix composites with large amounts of nanometer sized reinforcement particles, formed in-situ, can be fabricated by FSP without further consolidation. The microstructure was characterized using TEM, SEM and XRD. The Al-Mo intermetallic particles were formed in situ during FSP and were identified as Al_(12)Mo. These particles have an average size of ～200nm. Due to the fine dispersion of Al_(12)Mo particles, the aluminum matrix has an ultrafine-grained structure (～1μm). In addition, the reaction mechanism, and microstructural evolution during FSP, as well as the mechanical properties of the Al-Mo in situ composites, will be presented.