The Thermal Stability and Elevated Temperature Mechanical Properties of Spray-Deposited SiCp/Al–11.7Fe–1.3V–1.7Si Composite

The thermal stability and elevated temperature mechanical properties of SiCp/Al–11.7Fe–1.3V–1.7Si (Al–11.7Fe–1.3V–1.7Si reinforced with SiC particulates) composites sheets prepared by spray deposition (SD) → hot pressing → rolling process were investigated. The experimental results showed that the composite possessed high σ b (elevated temperature tensile strength), for instance, σ b was 315.8 MPa, which was tested at 315°C, meanwhile the figure was 232.6 MPa tested at 400°C, and the elongations were 2.5% and 1.4%, respectively. Furthermore, the composite sheets exhibited excellent thermal stability: the hardness showed no significant decline after annealing at 550°C for 200 h or at 600°C for 10 h. The good elevated temperature mechanical properties and excellent thermal stability should mainly be attributed to the formation of spherical α-Al12(Fe, V)3Si dispersed phase particulates in the aluminum matrix. Furthermore, the addition of SiC particles into the alloy is another important factor, which the following properties are responsible for. The resultant Si of the reaction between Al matrix and SiC particles diffused into Al matrix can stabilize α-Al12(Fe, V)3Si dispersed phase; in addition, the interface (Si layer) improved the wettability of Al/SiCP, hence, elevated the bonding between them. Furthermore, the fine Al4C3 phase also strengthened the matrix as a dispersion-strengthened phase. Meanwhile, load is transferred from Al matrix to SiC particles, which increased the cooling rate of the melt droplets and improved the solution strengthening and dispersion strengthening.