Abstract
This paper proposes a simple reactive melt infiltration process to improve the mechanical properties of silicon carbide (SiC) ceramics. SiC matrix composites were infiltrated by Al–Si (10 wt.%)–xTi melts at 900 °C for 4 h. The effects of Ti addition on the microstructure and mechanical properties of the composites were investigated. The results showed that the three-point bending strength, fracture toughness (by single-edge notched beam test), and fracture toughness (by Vickers indentation method) of the SiC ceramics increased most by 34.3%, 48.5%, and 128.5%, respectively, following an infiltration with the Al–Si (10 wt.%)–Ti (15 wt.%) melt. A distinct white reaction layer mainly containing a Ti3Si(Al)C2 phase was formed on the surface of the composites infiltrated by Al alloys containing Ti. Ti–Al intermetallic compounds were scattered in the inner regions of the composites. With the increase in the Ti content (from 0 to 15 wt.%) in the Al alloy, the relative contents of Ti3Si(Al)C2 and Ti–Al intermetallic compounds increased. Compared with the fabricated composite infiltrated by an Al alloy without Ti, the fabricated composites infiltrated by Al alloys containing Ti showed improved overall mechanical properties owing to formation of higher relative content Ti3Si(Al)C2 phase and small amounts of Ti–Al intermetallic compounds.
Highlights
Silicon carbide (SiC) ceramics are promising materials for applications in various industries owing to their high thermal and chemical stability, good resistance to corrosion and thermal shock, and high strength
Without Ti addition, the composites were composed of SiC, Al, and Si–xTi alloy (Si) infiltrated by the Al alloy, whereas the composites containing Ti were composed of Ti3 Si(Al)C2 as the main phase with small amounts of SiC and C
There was no obvious reaction layer on the surface of the composite infiltrated by the Al–Si alloy (Si: 10 wt.%) (Figure 2a)
Summary
Silicon carbide (SiC) ceramics are promising materials for applications in various industries owing to their high thermal and chemical stability, good resistance to corrosion and thermal shock, and high strength Their extensive application is limited due to their poor toughness [1,2,3]. To improve the strength and toughness of SiC ceramics, processing techniques, such as chemical vapor infiltration (CVI), liquid polymer infiltration, reactive melt infiltration (RMI), and spark plasma sintering (SPS), were applied [4,5,6]. Among these methods, RMI, which is most suitable for realizing the net shape of. The mechanical properties were measured using a universal testing machine and a Vickers indenter
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