| Metal matrix composites (MMCs) reinforced with high content particles were extend applied in aerospace, military, assemble and electric packaging fields due to its specific stiffness and strength, low density and advanced thermal properties. Some of those applications were involved dynamic loading. There is great different behavior between under the quasi-static and dynamic loading. It is necessary to study the dynamic properties to provide the reliable data for numerical calculation, engineering application and materials design.The dynamic properties of SiCp/2024Al with high particle content were investigated by experiment testing and numerical calculation method in present paper; it mainly includes content as following:The compression mechanical properties of SiCp/2024 reinforced with 40vol.%, 45vol.% and 50 vol.% particles were investigated by using split Hopkinson pressure bar(SHPB) and Instron materials testing machine, respectively. Before testing, samples were with casting, T6 and annealing solution-heat treated. The experiments were carried out in comparison at stain rates ranging from 0.001/s to 2500/s. The common SHPB technique showed limitation due to the brittle properties of metal matrix composites reinforced with high content particles. The pulse shaper technique was employed in dynamic compression. In order to obtain the reliable data, the copper disk with dimension ofФ5mm×1mm was chosen as pulse shaper to ensure the Samples are in dynamic stress equilibrium and have nearly constant strain rate over most of the test duration.The experiment results showed the composites display obviously different deformation mechanism at various strain rates. The composites show better elongation at high strain rate compared with under quasi-static loading. And at high strain rate, 40vol.% SiCp/2024Al deformed with good elongation from drug shape to shear fracture step by step, however, 45 and 50vol% SiCp/2024Al deformed with obvious brittle properties from shear fracture to split fracture. Compared with lower particle content (<30%) MMCs with good plastic deformation, the results showed that 40% as a critical volume fraction for SiCp/2024Al between plastic properties and brittle properties.The stress-strain curves at strain rates ranging from 0.001/s to 2500/s were obtained. The results showed that the composites exhibited high strain-rate sensitivity. The flow stress kept increase for 40 vol.% SiCp/2024Al and showed increase-decrease tendency for 50 vol.% SiCp/2024Al at strain rates ranging from 1250 to 2500/s, which maybe was caused by heat generated during adiabatic compression.The fracture surfaces were characterized by scanning electron microscopy. It is obvious that the matrix was softened /melted by heat generated during adiabatic compression. Combining the results of macro-deformation and the stress-strain curves, the results showed that the deformation mechanism of 40 vol.% SiCp/2024Al was controlled by matrix, and 50 vol.% SiCp/2024Al was controlled by net shape structure consisted by particles.Compressive properties of MMCs reinforced with high content partilces were investigated by using LS-DYNA. Axi-symmetric and three dimensional unit cell models with ellipsoids particles were employeed in numerical simulation. The effects of temperature rising caused by heat generated during adiabatic compression with Johnson-Cook model compared to Cowper-Symonds model and the thermal resident stress on the flow stress of SiCp/2024Al with high particle content were discussed. The results with Johnson-Cook model agreed well with the experiment results.And the effects of particle volume fraction, aspect ratio and particle shape on SiCp/2024Al dynamic properties were also discussed by using LS-DYNA. The numerical results showed that the effect of aspect ratio on flow stress of composites with lower particle content (10-30 vol.%) was less than on composites with high particle content. And the stress/strain curves of composites with low particle content was linear strain work hardening, however, the stress/strain curves of composites with 40% and 50% particle content showed increase-decrease tendency with increasing of strain. This agreed well with the experiments results of 40% is the critical volume fraction for properties of SiCp/2024Al.
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