Tensile Properties and Fracture Behavior of a Powder-Thixoformed 2024Al/SiCp Composite at Elevated Temperatures

In the present work, the tensile properties and fracture behavior of a 2024Al composite reinforced with 10 vol % SiCp and fabricated via powder thixoforming (PT) were studied at temperatures ranging from 25 degrees C to 300 degrees C with a strain rate of 0.05 s(-1), as well as the PT 2024 alloy. The results indicated that the tensile strengths of both the PT materials were all decreased with increasing the temperature, but the decrease rate of the composite was smaller than that of the 2024 alloy, and the composite exhibited higher tensile strength than that of the 2024 alloy at all of the employed testing temperatures due to the strengthening role of SiCp. Increasing temperature was beneficial for enhancing the ductility of materials, and the maximum elongation was reached at 250 degrees C. The elongation decrease over 250 degrees C was attributed to the cavity formation due to the debonding of the SiCp/Al interface and the fracturing of the matrix between SiCp. The fracture of the composite at room temperature initiated from the fracture of SiCp and the debonding of the SiCp/Al interface, but that at high temperatures was dominated by void nucleation and growth in the matrix besides the interface debonding.