Research Of Aluminum Matrix Composites Prepared By Accumulative Roll Bonding

Accumulative roll bonding (ARB) is used as a new method to fabricatealuminium-based metal matrix composites (AMMCs). The ARB method can solve theproblems such as non-uniform distribution, poor wettability of reinforcement, porosity,and poor economical efficiency in the traditional methods. ARB is one of the severeplastic deformation techniques used to fabricate ultrafine-grained materials. So, themechanical properties of AMMCs which fabricated by ARB process is influenced by thehard phase, the boundary hardening and dislocation hardening.Al/WC composites with high hardness, good mechanical properties, and wearresistance were produced by ARB process. The yield strength of the composites wasdetermined by tensile tests and compared with the calculated yield strength. The resultsindicated that there is a good agreement between the calculated yield strength andexperimental value. The strengthening mechanisms of those Al/WC composites areboundary hardening and dislocation hardening which introduced by severe plasticdeformation process and thermal expansion dislocation hardening, small subgrainhardening, Orowan hardening, secondary dislocation hardening, and geometricallynecessary dispersion hardening which introduced by WC phase.AMMCs reinforced with pure W particulates are manufactured through ARB. X-raydiffraction analysis reveals no Al-W intermetallics in the composites. The microstructureof the composites shows excellent W particle distribution in the matrixes. Tensile,hardness, and electrical conductance properties of the composites are determined. Theresults show that the introduction of4.2vol%W particles to Al matrix via ARB processleads to significantly enhanced mechanical properties and excellent electrical conductivity.Al/Al3Mg2composites were produced by ARB and vacuum annealing. Thereinforced phase in the composites is a type of Al-Mg intermetallic compound.Investigations regarding the hardness and tensile properties of the composites showed thatthe Vickers microhardness, tensile strength, and elongation of the Al/Al3Mg2compositesincreased with the number of ARB cycles. Compared with the annealed and ARB monolithic1060-Al, the Al/Al3Mg2composites showed excellent mechanical propertiesand low density.Al/Zn composites were fabricated using1060-Al plates and Zn particles by ARB andheat treatment. X-ray diffraction analysis reveals that most of the Zn phase in the finalAl/Zn composite disappeared in the Al matrix. Scanning electron microscopy andenergy-dispersive X-ray spectroscopy analyses revealed excellent solid solution regionsdistribution in the final Al/Zn composite. The final Al/Zn composite showed higherhardness values of the solid solution regions than the Al matrix. Compared with ARBedmonolithic1060-Al, the Al/Zn composites had higher strength without sacrificingductility.