Microstructure and mechanical property of the 2024Al matrix hybrid composite reinforced with recycled SiCp/2024Al composite particles

In the present work, the SiCp/2024Al composite chips have been recycled to be SiCp/2024Al composite particles (CPs for short) with average diameter of 900, 650 and 300 μm, which has been used as the reinforcement in the CP/2024Al hybrid composites prepared by pressure infiltration method. The CPs-Al interface was well bonded with an amorphous alumina interlayer. With the decrease of the dimension of the CPs from 900 to 300 μm, the tensile strength of the CP/2024Al hybrid composites was increased from 178 to 392 MPa, while the height difference of the LSCM profiles curves was decreased from 458 to 216 μm, and the length value of the LSCM profiles curves was increased from 1280 to 2184 μm, respectively. Based on the finite element analysis (FEA) simulation, the stress and strain concentration phenomenon of the CP/2024Al hybrid composites have been discussed. It has been found that the applied tensile stresses in the composites for the occurrence of debonding were increased with the decreased CPs size. Moreover, according to the Griffith's fracture criterion, the corresponding tensile strength of the composites with 300 μm CPs was 1.73 times of that with 900 μm CPs, which was close to the experimental results (2.15 times). It is suggested that the interfacial bonding strength should be improved to further increase the mechanical properties of the CP/2024Al hybrid composites.