Microstructures and mechanical properties of SiCp/AZ91 magnesium matrix nanocomposites processed by multidirectional forging

A particulate reinforced magnesium matrix nanocomposite was subjected to multidirectional forging (MDF). The results showed that the microstructure of the nanocomposite mainly consisted of some large initial grains and fine recrystallized grains along initial grain boundaries after 1 MDF pass. With increasing the MDF passes, the degree of dynamic recrystallization increased and ultrafine grains with average size of about 20 nm were observed in the nanocomposites after 6 MDF passes. The distribution of SiC nanoparticles in the nanocomposite was homogeneous outside some SiC nanoparticle dense zones after different MDF passes. Compared with typical basal texture obtained for 1 MDF pass, the basal pole intensity decreased firstly for 3 MDF pass and then increased for 6 MDF passes. Both ultimate tensile strength and elongation to fracture of the nanocomposite were enhanced with increasing the MDF passes, while yield strength decreased after 3 MDF passes and then increased slightly after 6 MDF passes. (C) 2014 Elsevier B.V. All rights reserved.

一种颗粒增强镁基纳米复合材料进行了多向锻造（MDF）。结果表明，经过1次MDF变形后，纳米复合材料的微观结构主要由一些大的初始晶粒以及沿初始晶界的细小再结晶晶粒组成。随着MDF变形次数的增加，动态再结晶程度提高，经过6次MDF变形后，在纳米复合材料中观察到平均尺寸约为20nm的超细晶粒。在不同次数的MDF变形后，纳米复合材料中SiC纳米颗粒在一些SiC纳米颗粒密集区之外分布均匀。与经过1次MDF变形获得的典型基面织构相比，基面极强度在经过3次MDF变形时首先降低，然后在经过6次MDF变形时又升高。纳米复合材料的极限抗拉强度和断裂伸长率都随着MDF变形次数的增加而提高，而屈服强度在经过3次MDF变形后降低，然后在经过6次MDF变形后又略有提高。（C）2014爱思唯尔有限公司。保留所有权利。