Abstract
Composites of 7055 aluminum (Al) matrix reinforced with SiC particles were prepared using the spray deposition method. The volume fraction of the phase reinforced with SiC particles was 17%. The effect of the introduction of SiC particles on the deposited microstructure and properties of the composites was studied in order to facilitate the follow-up study. The structure and element enrichment zone of spray-deposited SiCp/7055 Al matrix composites were studied by Optical Microscope (OM), X-ray diffraction (XRD), Scanning Electronic Microscopy (SEM) and Transmission electron microscopy (TEM). The results show that the reinforcement phases of the SiC particles were uniformly distributed on the macro and micro levels, and a few SiC particles were segregated into annular closed regions. C and Si on the surface of SiC particles diffused to the Al matrix. The distribution of the two elements was gradient weakening with SiC particles as the center, and the enrichment zones of Si, Mg and Cu formed in the middle of the closed annular area of a few SiC particles. The enrichment zones were mainly composed of alpha-Al, SiC, Al2CuMg, Al2Cu and MgZn2. AlCu and AlMgCu phase precipitate on the surface of the SiC particles, beside the particle boundary, and had the characteristics of preferred nucleation. They tended to grow at the edges and corners of SiC particles. It was observed that the formation of nanoparticles in the alloy had a pinning effect on dislocations. The different cooling rates of the SiC particles and the Al matrix led to different aluminum liquid particle sizes, ranging from 20 to 150 μm. In the region surrounded by SiC particles, the phenomenon of large particles extruding small particles was widespread. Tearing edges and cracks continued to propagate around the SiC particles, increasing their propagation journey and delaying the fracture of the materials.
Highlights
As-cast materials with a uniform composition, fine structure and high density can be obtained by spray deposition technology [1,2]
The different cooling rates of the SiC particles and the Al matrix led to different aluminum liquid particle sizes, ranging from 20 to 150 μm
Radial metallographic images of the center of the cross-section (Figure 1b(1)), the center of the radius of Figure 2 shows the metallographic structure of spray-deposited SiCp/7055 Al matrix composites the cross-section
Summary
As-cast materials with a uniform composition, fine structure and high density can be obtained by spray deposition technology [1,2]. Because the cooling rate of the stirring casting method and the melt infiltration method is low, the distribution of reinforcement particles is uneven, and the properties of the prepared materials are poor. SiC particulate-reinforced aluminum matrix composites prepared by spray deposition technology have the advantages of high Young’s modulus and good wear resistance [30]. Spray deposition technology has the advantages of a simple process, low segregation, a high cooling rate, and a fine microstructure. It has become one of the common methods used to prepare aluminum matrix composites [31,32]. The formation mechanism of the enrichment zones and the effect of the SiC particles on the microstructure and properties of the deposited SiC particles were studied
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
