Tensile deformation of nanocrystalline Al-matrix composites: Effects of the SiC particle and graphene

JM Zhan and WR Jian and XC Tang and YL Han and WH Li and XH Yao and LY Meng, COMPUTATIONAL MATERIALS SCIENCE, 156, 187-194 (2019).

DOI: 10.1016/j.commatsci.2018.09.050

Tensile deformation of SiC-reinforced Al-matrix composites are investigated via molecular dynamics simulations. To uncover the role of SiC particles in Al-matrix composites, the volume fraction, size and distribution are tailored, respectively. With increasing volume fraction of SiC particles, the elastic modulus and tensile strength of the composite are enhanced, while the ductility decreases. On the contrary, the increasing particle size at a constant volume fraction leads to an opposite trend. A sample with an inhomogeneous distribution of particles has a higher peak stress but a lower failure strain, since such an inhomogeneous distribution is more liable to block the slip of local dislocations, which may result in the localized strain distribution in the composite. By encapsulating SiC particles with graphene, the effect of graphene is also taken into account. Due to the high elastic modulus and the stronger bonding to SiC and Al, graphene enhances the elastic modulus of encapsulated SiC nanoparticles and improves the weak interface bonding between SiC and Al. Although the added graphene promotes the tensile strength of the composite, the ductility is not altered obviously due to the small size of particles.

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