| Particle-reinforced aluminum-based composites have high specific strength,specific stiffness,good wear resistance and dimensional stability,and have the dual advantages of ceramics and metals.They are used in aerospace,nuclear power,military,electronic and electrical,and automotive manufacturing.With the increase of the content of particle reinforcers,there are more defects in the interface between particle and matrix,and the poor deformation ability of coordination molding,which leads to the poor deformation ability and more internal defects of the composites,making it difficult to prepare large-size plates.In this paper,powder metallurgy is used to prepare aluminum-based composites(B4CP/6061Al)with 30 wt.%boron carbide particle(B4CP).The rolling process of the boron carbide aluminum matrix composites were numerically simulated and analyzed by ABAQUS numerical simulation software to study the stress and strain of the composites.And the rolling process of composite material was optimized,and the rolling window of composite material was established to guide the rolling experiment.On the basis of numerical simulation,aluminum matrix composites were rolled under different process parameters.The forming process,internal particle distribution and microstructure evolution process of particle/matrix interface of composite sheet were studied under different process parameters.The mechanical properties of composite sheets were studied and analyzed,and the strengthening mechanism was discussed.The fracture was observed and the fracture mechanism was explored.The rolled composites were treated with high-energy pulse current to explore the influence of pulse current on the internal microstructure morphology of the composites.The internal mechanism of the healing effect of pulse current on the interfacial microcracks and micropores of sheet was studied.The effect of pulse current on interface bonding performance was analyzed,and the mechanical properties after pulse current treatment were tested and analyzed.The main research contents of this paper include:(1)In the numerical simulation process of hot rolling of B4CP/6061Al composites,the stress on the surface of the sheet is greater than that on the center of the sheet,and the stress changes from tensile stress to compressive stress,so the surface tends to produce more plastic flow,and the flow stress increases with the increase of strain rate,and decreases with the increase of temperature.(2)The B4C particles are distributed uniformly in the Al matrix.The Al matrix is dominated by the little angle grain boundaries and the average grain size is refined to 3.86?m after hot rolling.In the process of hot rolling,the soft Al matrix will produce obvious plastic flow under the action of pressure,which will promote the uniform dispersion of B4C particles at the same time,so as to improve the porosity and agglomeration problems in the material.(3)After hot rolling,the tensile strength of the sheet increases with the increase of the reduction amount.The B4C particles of the rolled B4CP/6061Al composites are uniformly distributed in the continuous Al matrix,and show good bonding interface and high dislocation density.After pulse current treatment,the tensile strength and elongation of B4CP/6061Al composites are improved,and the plastic loss of the composites after rolling deformation is obviously improved.(4)No precipitate was found in Al matrix of rolled composites after pulsed current treatment.After pulsed current treatment,obvious recrystallization occurred around the B4C particles,and the average grain size of the aluminum matrix grew from 3.86?m to 3.96?m because of the Joule heating effect.However,the grain boundaries in the aluminum matrix were still dominated by the little angle grain boundaries.After pulse current treatment,the effect of electronic wind effectively promoted the dislocation movement,and the recrystallization phenomenon occurred inside the material,the proportion of which reached 16.4%. |
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