The Study On SiC-Al Composite Powder Particle Size Distribution And Mechanical Properties Of Equal Channel Angular Pressing And Torsion

Aluminum silicon carbide composites have excellent physical and mechanicalproperties such as specific strength, specific stiffness, wear resistance and low thermalexpansion coefficient. Traditional powder metallurgy process generally generate coarsegrains at high temperature, the aluminum substrate oxidation and other tissue defectssuch as segregation. And large plastic deformation process can be implemented at alower temperature to the density of the powder materials, Equal Channel AngularPressing and Torsion(ECAPT) was a new type of composite large plastic deformationprocess base on the Equal Channel Angular Pressing(ECAP) and TwistExtrusion(TE).Composite powder occur implement fully dense under the intense shearstrain accumulation of the seven deformation zones and three shear plane. The grainwould be refinement and uniform at the same time.PFC3D software was first introduced in this paper to simulate the ECAPT process.The numerical simulation results show that the shear process of ECAPT effectivelypromoted the density of the powder, SiC particles in the deformation process showedthe characteristics of the general order and partial disorder, SiC particle clustersscattered displacement to improve the uniformity of material performance. Through thecontact force analysis we know that the resistance of TE channel have the effect of backpressure, the tensile stress in the outer corner into compressive stress.Experimental results show that10%content of SiCp/Al composite powder after atime ECAPT can complete basic density. The experimental results of differenttemperature, time and ratio show that under the ECAPT process, the maximum densityand enhanced phase content are the main factors, which affect the mechanical propertiesof SiCp/Al composite. Respectively, the hardness and strength, enhanced with theincrease of density increases and the increase of phase content. The main strengtheningmechanism of ECAPT including load transfer mechanism, dislocation strengtheningmechanism and the grain refinement strengthening mechanism. With the increase of thetime, the macroscopic strength improve a little, but the interface reaction can effectivelyenhance the interface bonding material, improve the corrosion resistance.