Microstructure and mechanical properties of SiCp/Al composite fabricated by concurrent wire-powder feeding laser deposition

Abstract

In this study, the SiCp/Al matrix composites was fabricated by concurrent wire-powder feeding laser deposition (CWPLD). The microstructure and mechanical properties of the fabricated SiCp/Al composites were studied. The microstructure of fabricated composites consisted of Al matrix, SiC and reaction product Al4C3. The size of α-Al grain (mean area: 275.0 μm2) was much smaller than that of Al specimen fabricated by wire feeding laser deposition (WLD) (mean area: 1544.4 μm2). SiC and Flaky Al4C3 were non-uniformly distributed in the matrix. Al4C3 platelets distributed discontinuously at the interface between unmelted SiC and Al. Due to the inhomogeneous distribution of SiC and Al4C3, the Vickers hardness of the fabricated composites fluctuated violently, ranging from 85 HV to 120 HV. The ductility of the fabricated composites (3.75%) was lower than that of the Al specimen (8.94%) fabricated by WLD. The tensile strength of the fabricated composites (246.0 MPa) was higher than that of the Al specimen fabricated by WLD (230.8 MPa). In the tensile test, only SiC fracture were found in the fracture observation. The bonding strength of interface between SiC and Al was higher than strengths of SiC particle and Al matrix. The debonding between SiC and the Al matrix was not found on the fracture surface of tensile specimens.

Keywords

• SiCp/Al composites
• Concurrent wire and powder feeding laser deposition
• Microstructures
• Mechanical properties
• Interface