The Effect Of Spatial Structure On The Mechanical Properties Of Steel Matrix Composites

The traditional metal matrix composites reinforced by ceramic particles(MMCs)Have favorable strength and abrasive resistance because of ceramic particles dispersively distributed in the matrix,but this structure can not bring out the best of synergy between different components.The spatial structure toughening is a new way to increase the performance of MMCs,that the MMCs is separated into two areas distributed evenly in space,namely reinforce particles rich areas(also called composites areas)and pure matrix areas(also called toughening areas).In this work,the spatial structure composites in 40Cr matrix reinforced by ZrO2 and Al2O3(ZTA)ceramic particles are prepared by squeeze casting.The effects of three kinds of consecutive space structural systems on mechanical properties of the spatial structure composites are researched,such as circular column,quadrangular and hexagonal prisms structural systems,under condition of 45%(volume fraction)composites areas.And the distributions of stress and strain inside the spatial structure composites are simulated by ANSYS software.The results shows that the inward of are spatial structure composites by squeeze casting is the network of MMCS and pure matrix areas interspersed with each other,the combinations of each other are firm without shrinkage cavity and porosity.The combination between ceramic particles and matrix is tight and homogeneous.The compression and three-point bending tests for different spatial structure composites are simulated and analyzed by finite element method.The stress concentration and strain energy concentration phenomenons are likely to cause by the acute angle effect,within quadrangular and hexagonal prisms structural spatial composites.The stress and strain energy of circular column structural spatial composites are the smallest,and distribution is uniform.So the strength and plasticity of 3D-MMCs/steel with circular column structure is the highest by simulating.The physical experiment results of compression and three-point bending accord with the computer simulation results,as well as the performance of 3D-MMCs/steel with circular column structure is the best.The compressive strength and strain of circular column 3D-MMCs/steel composite respectively are 900MPa and 19.1%in compression test.The compressive strength increases 47%than that of homogeneous composite(traditional composite),and respectively increases 26.76%and 10.84%than that of quadrangular and hexagonal prisms structural spatial composites.The bending strength and strain of circular column 3D-MMCs/steel composite respectively are 706MPa and 5.9%in three-point bending test.The bending strength increases 89.78%than that of homogeneous composite,and respectively increases 18.06%and 3.82%than that of quadrangular and hexagonal prisms structural spatial composites.The performances of three kinds of spatial structure composites are better than traditional composites because the pure steel matrix areas block the motion and change the propagation direction of cracks.Because of the three dimensional cross network structure within spatial structure composites and the interlock effect between the reinforce particles rich areas and the pure matrix areas,the spatial structure composites have better mechanical properties than homogeneous composites.In this work,the effects of spatial distribution of reinforce particles rich areas on mechanical properties are revealed,combining the theoretical analysis and the mechanical tests.And it maybe provide a strong basis to optimizing the spatial structure of metal matrix composites.