## 6 Summary  
In this paper, SiCp/6061 Al composites with volume fractions of 5%, 10%, and 15% were prepared by vacuum hot pressing sintering. The microstructure and fracture morphology were observed and analyzed. The elastic-plastic behavior of the 6061 Al matrix in composites was studied by using the load-displacement curve measured by the nanoindentation mechanical test, and the plastic constitutive equation was established. The image processing technology was used to identify the geometric characteristics of the SiCp from the metallographic structure, and the RVE finite element model was established to simulate  
Figure 10: **(a-c)** are the RVE models of the SiCp/6061 Al composites with volume fractions of 5%, 10%, and 15%, respectively. **(d)** The nominal stress–strain curves of the SiCp/6061 Al composites with volume fractions of 5%, 10%, and 15% were compared with the simulation results. The plastic strain nephogram of the SiCp/6061 Al composites with **(e–g)** volume fractions of 5%, 10%, and 15% after RVE model fracture, respectively.  
the deformation and fracture process of the SiC/6061 Al composites under uniaxial tension. The effects of the interface strength and SiCp volume fraction on the microscopic deformation and fracture characteristics of SiC/6061 Al composites were revealed. The main conclusions are as follows:  
1. The results of the nanoindentation test show that the yield strength of the 6061 Al matrix with a 10% volume fraction of SiCp increased about 31 MPa. Based on [PERSON]'s inverse analysis algorithm, the plastic constitutive equation of 6061 Al matrix was established as follows: \[\sigma=230*\left(1+301.3*\varepsilon_{p}\right)^{0.097}.\]
2. The deformation and fracture mechanism of the SiCp/6061 Al composites under tensile load was revealed. The first stage was uniform deformation. The Mises stress and plastic strain distribution of the matrix part in the model were relatively uniform. In the second stage, damage failure began to appear in the interface between the SiCp-reinforced phase and the 6061 Al matrix. In the third stage, the 6061 Al matrix bore most of the load near the failure interface, resulting in a significant increase in the plastic strain value, the first damage occurred, and the damage increased further and developed into a crack.
3. With the increase in the interface strength, the occurrence of the interface failure was delayed during the tensile deformation, and the corresponding fracture strain also increased. The overall mechanical properties of the SiCp/6061 Al composites were significantly improved by increasing the interfacial strength of the composites.
4. The yield strength of the SiCp/6061 Al composites increased with the increase in the SiCp volume fraction, and the fracture strain rate decreased. The average equivalent stress of the SiC component in the SiCp/6061 Al composites under a yield state reached about 400 MPa. The average equivalent stress of the 6061 Al component was about 230 MPa. The average equivalent stress of the composite material as a whole was around 250 MPa, and the bearing effect of the particle-reinforced phase was obvious.  
Conceptualization, H.W. and G.J.; methodology, H.W. and G.J.; Experimental Design, H.W. and G.J.; Calculation and analysis, H.W.; Consulting information, Y.X. and Y.L.; Collecting data, Y.X. and Y.L.; Experiments, Y.X. and Y.L.; Paper writing, H.W.; Paper modification, G.J. All authors have read and agreed to the published version of the manuscript.  
This study was funded by the key scientific research project of Henan Province, China (16A430037).  
Not applicable.  
The authors declare no conflict of interest.