Behaviors of Oxide Film during Semisolid Brazing of SiC_p/6063Al Composite Materials

Abstract

The semisolid brazing of SiCp/6063Al under an applied pressure using Zn-Al-Cu filler metal was investigated. The samples to be joined were heated from 380°C to 382°C, 386°C, 392°C, and 410°C under a constant pressure of 10 MPa, respectively. Effects of the temperature on microstructural evolution and deformation behavior of the filler metal, interfacial structure, and shear strength of the bonded joint were discussed, and the disruption behavior of the surface oxide film was studied. The results show that, after heating, the solid grains of the filler metal transform into a globular structure surrounded by liquid. The degree of sphericity and the liquid fraction tend to improve with increasing temperature. During the heating process, the deformation of the filler metal is first accomplished by plastic deformation of solid grains and then by intergrain sliding and liquid flow. The surface oxides are broken and stripped by a cocontribution of compressive and shear stress which is caused by depressing and sliding of solid grains along the composites. It is found that the heating of 380°C to 392°C under pressure is the optimum condition to disrupt the surface oxide films and obtain sound bonds. The mechanical test results show that the maximum shear strength of the bond joints is as high as 105 MPa, reaching 78% that of the parent materials.

Semisolid Compression Brazing of Al50Si Alloy Using Zn-Al-Cu Filler Metal Assisted by SiC Particles

“…High volume fraction of solid phases in the filler metal could produce high compression to the base metal and therefore is benefit for the oxide film removal during semisolid compression brazing process [8]. However, fluidity and wetting of the filler metal decreases when filler metal has an excessive solid fraction.…”

“…In our previous works, the semisolid compression brazing has been used to join SiC p /Al composites. e oxide film on the surface of SiC p /Al composites was effectively broken by compression and friction of the solid grains in the semisolid filler under constant pressure [8]. However, the oxide film on the surface of Al50Si alloys cannot be completely Advances in Materials Science and Engineering disrupted by these solid grains in this work.…”

“…Mechanical energy-assisted semisolid brazing is a promising method that has the potential to overcome the oxide problem. e compression and friction of the solid grains in the filler metal can result in fragmentation of the surface oxide layers under the mechanical energies, and therefore, bond strengths can be improved dramatically [4][5][6][7][8]. However, these methods are of limited use for aluminum alloys due to the presence of more continuous surface oxide films on such alloys.…”

Nickel-plated SiCp/Al composites brazed in the air: microstructure and mechanical properties of brazed joints under different processes

“…SiC p /Al MMCs consisted of SiC particle ceramic phase and aluminum matrix [12,13] . The secondary processing of SiC p /Al MMCs is very di cult because of the large difference in performance between the two [14,15] . The poor wettability of the SiC ceramic particles reinforced phase also makes it di cult to successfully connect the SiC p /Al MMCs by conventional connection methods [16] .…”

Joining of Hypereutectic Al-50Si Alloys Using Lead-Free Brazing Filler Glass in Air

“…As the chemical properties of silicon carbide particles are quite different with the base aluminum alloy, the joining of SiC p /Al MMCs has been a difficult point. Joining methods for SiC p /Al MMCs include flux-free diffusion joining [ 4 ], transient liquid phase bonding (TLP) [ 9 ], vacuum brazing [ 10 ], ultrasonic brazing [ 11 ], friction stir welding [ 3 ], mechanical vibration agitation brazing [ 12 , 13 ] and semi-solid welding [ 14 , 15 ], etc. Among the above-mentioned joining methods, brazing has good joining effect and economic efficiency.…”