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• Al-7075 was reinforced by different contents of Fe-based metallic glass particles. • The composites were prepared by spark plasma sintering and hot extrusion. • The composites possess higher mechanical properties than unreinforced Al-7075. • The composites are reinforced mainly by thermal mismatch and grain refinement. Metallic glass (MG) reinforced aluminum matrix composites (AMCs) have attracted the interest of many researchers in the past few years. In this study, Fe 50 Cr 25 Mo 9 B 13 C 3 metallic glass (FMG) particles reinforced 7075 aluminum matrix (Al-7075) composites were prepared by spark plasma sintering (SPS) technique. The microstructure of the composites showed good interface bonding between the FMG particles and the matrix. The micro-hardness of the composite with 30 vol% FMG particles reached 160.63 HV, which was increased by 30% compared with that of Al-7075 (119.3 HV). The ultimate compression strength (UCS) of the composite was also improved significantly from 596 MPa for Al-7075 matrix to 749 MPa for the composite reinforced with 30 vol% FMG particles, and the compression strain of the composite reached 22%. These results indicate that the mechanical properties of the composites can be enhanced by adding high volume fraction FMG particles. The enhancement of the strength is resulted from multiple strengthening mechanisms, and the main contributions come from the thermal mismatch and grain refinement. [ABSTRACT FROM AUTHOR]

Graphene oxide-carbon nanotubes hybrid reinforced aluminum matrix composites (GO-CNT/Al) were prepared by powder metallurgy followed by hot extrusion. The strength of the composites was improved by the synergistic effect of carbon nanotubes, in-situ Al 4 C 3 and graphene oxide. Moreover, due to the partially recrystallization of Al matrix promoted by Al 4 C 3 , the matrix exhibits a bimodal grain distribution, which helps to enhance strain-hardening and consequently uniform tensile ductility at high flow stresses. Hence the bimodal grain structure of the matrix combined with the nano-reinforcements leads to enhancing of the strength and ductility synergy. The composite shows a high tensile strength of 249 MPa (175 MPa of pure Al) and keeps almost similar tensile ductility with pure Al (uniform elongation of ~23.1%). • The structure changes of graphene oxide and carbon nanotubes during ball milling were revealed. • The influence of reinforcement dimension on the strengthening mechanism of aluminum matrix composites was emphasized. • The balance between strength and ductility is achieved by different dimension reinforcements and bimodal grain distribution. [ABSTRACT FROM AUTHOR]

High elongation aluminum matrix composites reinforced with carbon nanotubes (CNTs) were prepared by flake powder metallurgy, and densified by hot extrusion with a high extrusion ratio. After hot extrusion, fine and equiaxed grains were obtained in 2 wt% CNT/Al composite, and interfacial product (Al 4 C 3) as well as bridge-connected CNTs aligned along the extrusion direction were found both in 1 wt% CNT/Al and 2 wt% CNT/Al composites. Both composites obtained high elongation while their strength was enhanced. Especially the elongation of 2 wt% CNT/Al composite is comparable to that of pure Al prepared by the same method, which reached about 30%. The good ductility mainly attributes to firm interfacial combination between CNTs and matrix, fine and equiaxed grains formed by dynamic recrystallization during hot extrusion, and bridge-connected CNTs aligned along the extrusion direction. Unlabelled Image • CNT/Al composites and pure Al were fabricated by flake powder metallurgy • The dynamic recrystallization occurred in 2 wt% CNT/Al composite during hot extrusion • The elongation of 2 wt% CNT/Al composite is comparable to that of pure Al prepared by the same method • The bridge-connected CNTs is helpful to improve the elongation of composite [ABSTRACT FROM AUTHOR]