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

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

Microstructure evolution, interface and mechanical properties of SiCp/2A14 joint during laser keyhole welding

Welding problems have restricted the applications of lightweight SiCp/Al composites in aerospace. In this work, the controllability of the keyhole mode, nucleation mechanism, and mechanical properties of the laser-welding process are studied in detail. The extrusion effect formed by the open keyhole pushes SiC particles to the bottom of the molten pool. To observe the nucleation and growth mechanism of the Al4C3 of keyhole laser-welded SiC/2A14Al composites, the dissolution–precipitation behavior of the SiC particles and growth behavior of the Al4C3 tip were observed. Owing to its high chemical properties, Al4C3 mainly begins nucleating from the open edges of the SiC particles and its formation is mainly distributed along the direction of Al grains. Al4C3 was the main crack source and propagation path while the small-sized SiC particles hindered the crack propagation. This work innovatively regulates the keyhole mode to achieve ‘small damage breakdown’ laser welding, greatly reducing the volume fraction of Al4C3. It also provides new insight into fusion welding of SiC particle-reinforced Al matrix composites

Effect of interface evolution on thermal conductivity of vacuum hot pressed SiC/Al composites

International audienc

Structural modeling and mechanical behavior of Metal-Porous-Polymer-Composites (MPPCs) with different polymer volume fractions

International audienceSince the past five decades, the study of new materials has become attractive in both scientific research and industrial applications. For purpose of enhancing mechanical properties of metallic foam, a new composite entitled “Metal-Porous-Polymer-Composite (MPPC)” consisting of open-cell metallic foam and filling polymers was developed by infiltrating the filling polymers throughout the connected pores in open-cell metallic foam. Based on a three-dimensional (3D) structural modeling, microscopic structural models of Al metallic foam and MPPCs with spherical pores and Kelvin’s pores are established in the finite element code. Introducing the elastoplastic mechanical properties, the polymer–metal interfacial behaviors and the proper loads and boundary conditions on these structural models of Al metallic foam and MPPCs, the numerical compressive behaviors of Al metallic foam and PA6/Al & LDPE/Al MPPCs are successfully performed. The results show that the mechanical properties of PA6/Al & LDPE/Al MPPCs are mainly influenced by the filling polymers, the kind of pores, the pore size, the polymer–metal interface, the polymer volume fraction and the distribution of pores, respectively. It means that a good understanding can be provided concerning the deformation mechanism and engineering applications of both Al metallic foam and MPPCs

Effect of Interface Evolution on Thermal Conductivity of Vacuum Hot Pressed SiC/Al Composites

International audienc

Structural Modeling and Thermal Conductivity of Graphite Film Reinforced Aluminum Matrix Laminated Composites

Abstract: Excellent thermal conductivities of thermal management materials are expected to ensure the timely heat dissipation in lots of engineering applications and electronic devices. High in-plane thermal conductivity of laminated composites has become increasing significant for high energy and power density electronic devices. In this study, the continuous graphite film/aluminum (Gr film/Al) laminated composites were fabricated by vacuum hot pressing. In-plane and out-of-plane thermal conductivity of Gr film/Al laminated composites are tested. Two-dimensional structural models of Gr film/Al laminated composites are established, in which volume fraction, interfacial property, punching zone and orientation angle of Gr films can be controlled according to their actual composite microstructures. The effects of volume fraction and interfacial property on the thermal conductivity of Gr film/Al laminated composites are investigated. Two ways to reduce anisotropy of thermal conductivity are introduction of punching zones and control of Gr orientation, which are verified to be effective. On basis of the analysis above, a good understanding can be brought out for extensive thermal management applications of Gr/Al composites