Effects of Matrix Components on Microstructure and Properties of SiC_P/Al-Fe-V-Si Composites

Abstract

Spray deposited SiCP/Al-Fe-V-Si composites were densified by twice hot pressing and subsequently multi-pass hot rolling. Scanning electron microscope, transmission electron microscope and tensile test were used, and the effect of matrix alloy components and Fe/V ratio on microstructure, mechanical properties and heat resistance of the composites were analyzed.The results show that the as-rolled composites have high volume fraction Al12(Fe,V)3Si dispersoids, and volume fraction of the dispersoids increases with Fe content increasing. Volume fraction of Al12(Fe,V)3Si dispersoids is up to 40% when Fe content of the matrix alloy is 11.5%(mass fraction). Al12(Fe,V)3Si dispersoids with the diameter of 50-80nm are distributed along the grain boundaries, and exhibit excellent thermal stability up to 500℃. However, above 500℃ the Fe atoms diffuse in the form of bulk diffusion, and accordingly the dispersoids both along the grain boundaries and in the grains become coarsened at a relative high velocity. Coarsening velocity of Al12(Fe,V)3Si dispersoids falls with the increase of Fe/V ratio. Strength of the composite increases with volume fraction of Al12(Fe,V)3Si dispersoid increasing, and decreases with the tensile temperature rising; the elongation of the composite decreases both with rise of volume fraction of Al12(Fe,V)3Si dispersoid and tensile temperature.

Keywords

• Al-matrix composite
• spray deposition
• matrix component
• particle reinforcement
• microstructure