Microstructure and mechanical behavior of polymer-derived in-situ ceramic reinforced lightweight aluminum matrix composite

[摘要] Metal/alloy matrices have been previously reinforced with ceramic nanoparticles, but such reinforcements tend to agglomerate, have weak interfaces, and are expensive. Polymer-derived ceramics (PDCs) based composites can potentially overcome these shortcomings. These composites are obtained from the pre-ceramic polymers after pyrolysis. These polymers are inexpensive, can be fragmented to the nanoscale, and pyrolyzed in-situ. Friction stir processing (FSP) was used to fragment and disperse the polymer within an Al-Mg alloy. The PDC particles pinned the dislocations and grain boundaries. The composite exhibited a microstructure resulting from dynamic recrystallization with an average grain size of similar to 1 mu m. It also exhibited both high strength (96% and 24% improvement in the yield and tensile strength, respectively) and good ductility. Interestingly, the serrations in the tensile curves commonly observed in Al-Mg alloys due to the Portevin-Le Chatelier (PLC) effect was reduced in the composite. (C) 2021 Elsevier B.V. All rights reserved.

[发布日期] 2021-11-05

[关键词] Polymer-derived ceramic;Friction stir processing;Metal matrix composite;In-situ;Microstructure