Abstract
Hot deformation at elevated temperature is essential to densify particle-reinforced aluminum matrix composites (AMCs) and improve their performance. However, hot deformation behavior of the AMCs is sensitive to the variation of hot-processing parameters. In this paper, optimal processing parameters of dual-scale SiCp/A356 composites were determined to explore the control strategy of the microstructure. Hot-compression tests were conducted at temperatures ranging from 460 to 520 °C under strain rates from 0.01 to 5 s−1. Constitutive equation and processing maps were presented to determine the hot-processing parameters. Microstructure evolution of the dual-scale SiCp/A356 composites was analyzed. The strain rate of 0.62–5 s−1 and deformation temperature of 495–518 °C is suitable for the hot processing. The number of dynamic recrystallization (DRX) grains in the “safe” domains is larger and the dislocation density is lower compared to those of instability domains. DRX grains mainly occurred around SiC particles. The presence of SiC particles can promote effectively the DRX nucleation, which results in the dynamic softening mechanism of the dual-scale SiCp/A356 composites being dominated by DRX.
Highlights
Due to their low density and expansion coefficient, high specific strength and specific modulus, good high-temperature performance and wear resistance, SiC particle-reinforced Al–Si matrix (A356, A357) materials are appropriate for weight reduction in the field of the automotive industry and other engineering applications [1,2,3,4]
The presence of SiC particles can promote effectively the DRX nucleation, which results in the dynamic softening mechanism of the dual-scale SiCp/A356 composites being dominated by DRX
The results show that the correlation coefficient is 0.951(R > 0.95) and the average relative error is 4.26% (AARE < 5%)
Summary
Due to their low density and expansion coefficient, high specific strength and specific modulus, good high-temperature performance and wear resistance, SiC particle-reinforced Al–Si matrix (A356, A357) materials are appropriate for weight reduction in the field of the automotive industry and other engineering applications [1,2,3,4]. The SiCp/Al–Si matrix composite is usually fabricated using either micro-sized or nano-sized SiC particles. The properties of SiCp/Al–Si composites depend on the amount and size of SiC particles. SiC particles could improve the hardness and strength of Al–Si matrix composites at the expense of plasticity. While nano-sized SiC particles could improve the plasticity of Al–Si matrix composites, the enhancement of strength and wear resistance is not remarkable. DRV is prone to occur in high stacking-fault energy metals, because of the easy movement of dislocations. DRX rarely occurs in aluminum alloy and its composites because of the high stacking fault energy of these materials [19]. Research of hot deformation behavior of particle-reinforced aluminum matrix composites (AMCs) is mainly focused on single micron or nano reinforced particles [17,22,23]. Hot deformation behavior was analyzed by the dislocation particulate interactions model
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