Synthesis and forming behavior of aluminum-based hybrid powder metallurgic composites
Aluminium-based metal matrix composites were synthesized from Al、TiO2 and Gr powder mixtures using the powder metallurgy technique and their forming characteristics were studied during cold upsetting.The powder preforms were pressed with a 40 kN hydraulic press with appropriate punches and dies,and then sintered in an electric furnace at 590 ℃ for 3 h in an air atmosphere.The sintered preforms were subjected to incremental compressive loads of 10 kN until cracks were found on the free surface.Axial stress(σz),hoop stress(σθ),mean stress(σm)and effective stress(σeff)were calculated for all pre-forms,which are related to the axial strain(εz).The densification behavior of the composites under axial strain(εz)and transverse strain was investigated.It is observed that the addition of 5％TiO2 into the Al matrix increases σz,σθ,and σm.The addition of both TiO2 and Gr reinforce-ments reduces the densification and deformation characteristics of the sintered preforms during cold upsetting.
metal matrix compositealuminumcold upsettingpowder metallurgyworkability
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