| Modern industry urgently needs structural parts that can work under high loads and strong wear conditions.Ceramic particle-reinforced metal matrix composites combine the performance advantages of both metal and ceramic particles,can overcome each other’s deficiencies,and are highly designable,which is one of the development directions of high-strength and strong wear-resistant materials.In this paper,we introduce computational simulation technology into the design and optimization of spatial configuration composites to study the spatial configuration structure of ZTAp/40 Cr steel composites and the influence law of configuration parameters on the mechanical properties of composites,optimize the structure of new configuration composites,and predict the mechanical properties of configuration composites.Predicting the mechanical properties of configuration composites provides an important theoretical basis and engineering guidance for the subsequent design of configuration composites.The specific work is as follows.(1)A multi-scale simulation method was used to realize the simulation of the macroscopic mechanical properties of the three-dimensional interpenetrating configuration composites of 35vol% and 50vol% ZTAp/40 Cr steel and the analysis of the microscopic failure mechanisms.The results show that the mechanical properties of ZTAp/40 Cr steel three-dimensional interpenetrating network composites can be effectively calculated by using the multiscale simulation method.For the 3D interpenetrated composites,different volume fractions of the composite zone have an important impact on its strength and toughness,where the yield strengths of 35vol%and 50vol% 3D interpenetrated composites are 1412.5 MPa and 1226.3 MPa,and the ultimate compressive strengths are 1712.1 MPa and 1302 MPa,corresponding to the strain values 0.078 and 0.051.uniformly distributed composites,the yield strength and ultimate compressive strength are 1220.2 MPa and 1313.3 MPa,respectively;the increase of interfacial strength of reinforcing particles will increase the compressive strength of the composites;with the decrease of interfacial fracture energy,the compressive strength and plasticity will also decrease accordingly.(2)In order to solve the problems caused by structural and boundary simplifications in multi-scale simulations,an integrated structural simulation method is proposed,and the effects of different configuration parameters(particle shape,particle size,volume fraction of configuration zone and specimen size)on the mechanical properties and failure of ZTAp/40 Cr steel spherical spatial dot matrix composites are analyzed by this method.The results show that for different particle shapes,the smoother and longer reinforcement particle shapes can improve the mechanical properties of the composites;for different sizes of reinforcement particles(1.25 mm,1.5 mm,1.75 mm,2 mm and 2.25 mm),the composites with small size reinforcement particles have higher strength,plasticity and toughness,and as the size of reinforcement particles increases,cracks gradually appear in the top and bottom spherical regions of the specimens.The energy absorption of the larger reinforcing particles is slower than that of the small reinforcing particle size specimens;for different volume fractions of the configuration zone(10%,15%,20%,25%,30%,35%and 40%),the composites with smaller volume fractions of the configuration zone exhibit higher fracture strain and ultimate compressive strength,and at a volume fraction of about 25%,the fracture strain and ultimate For different specimen sizes(H/D=1,2,3 and 4),the displacement corresponding to the ultimate compressive strength is proportional to the specimen length,and the time required to reach damage is shorter for small-size rectangular specimens than for large-size specimens,and the energy absorption of large-size specimens is relatively faster than that of small The energy absorption of large-size specimens is faster than that of small-size specimens.(3)Using an integrated structural simulation method,the laws of different configuration structures on the changes of mechanical properties of composites were studied,and the effects of macrostructure on the strength and toughness and failure behavior of the configuration composites were analyzed.The results show that the conformational design can improve the ultimate compressive strength and fracture strain of composites,and the relationship between ultimate compressive strength and fracture strain is: spherical spatial dot matrix > 3D interpenetrating network > uniform distribution;the conformational structure can concentrate the cracks of composites to the middle region of the material,and the main cracks of uniformly distributed composites will appear in the lower part of the material,and the stress-strain curve of the conformational structure(especially the spherical spatial dot matrix structure)The stress-strain curves of the constitutive structures(especially the spherical spatial dot matrix structure)are much lower than those of the uniformly distributed composites and show better toughness;the critical units of all three structural composites mainly show triaxial compressive stress and brittle fracture characteristics;the final failure form of the three-dimensional interpenetrating network structure is cylindrical cracks,and the uniformly distributed composites have different forms of transverse and inclined cracks,and the final stabilization energy of the spherical spatial dot matrix is about twice that of the uniformly distributed composites.The final stabilization energy of spherical spatial dot matrix is about twice as much as that of uniformly distributed composite.Comparison of stress concentration coefficient of reinforced particles:spherical spatial dot matrix > 3D interpenetrating network > uniform distribution,spherical spatial dot matrix structure has better performance in load carrying capacity.(4)Based on the aforementioned analysis,in order to further improve the mechanical properties of the configuration composites,optimization strategies are proposed for different configurations,the mechanical properties performance of different structural composites after optimization is analyzed,and the spherical spatially graded composites with more excellent mechanical properties are proposed for different structural characteristics,and their mechanical properties and failure forms are predicted.The results show that: the staggered structure can make the spherical spatially graded composites reach the compressive limit later,the reinforcing particles after the staggered spatial spheres have an improvement on the composite in load carrying capacity,the fracture strain of spherical spatially graded composites after the staggered spatial spheres is 0.077,and the ultimate compressive strength is1753.1MPa;the smoothing of columnar intersections can make the reinforcing particles inside the composite in load carrying capacity The ultimate compressive strength is 1761.9MPa and the fracture strain is 0.074 after smoothing at column intersections;the spherical spatial gradation composite formed by different composite zone size gradations,the spherical gradation can increase the energy required for crack expansion,so that the cracks are not concentrated in the middle region of the material,which is conducive to the dispersion of internal failure stress and enhance the mechanical properties of the composites of the configuration The ultimate compressive strength is 1853.6 MPa and the fracture strain is 0.072.The higher the gradation level,the first failure occurs in the small composite spheres,and the spheres in the composite zone with larger gradation levels can provide more load carrying capacity. |
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