Research Progress on Microstructure Characterization of Silicon Carbide Fibers

Ceramic matrix composites have excellent properties such as high temperature resistance and oxidation resistance, and have good application prospects in the hot end parts of engines. In ceramic matrix composites, the microstructure composition of silicon carbide fibers determines their macroscopic properties. Therefore, this article takes silicon carbide fiber as the research object, summarizes the existing SiC fibers structure, composition, and morphology characterization methods, compares the development and advantages and disadvantages of XRD, SEM, TEM and other testing equipment analysis, and proposes The problems of sample preparation, surface defects and internal structure changes in the microstructure characterization of silicon carbide fibers are discussed, which provides a reference for the preparation of high-performance SiC fibers and the improvement of their characterization work.

Enhanced Fluidity of ZL205A Alloy with the Combined Addition of Al–Ti–C and La

The effects of Al–Ti–C and La on the fluidity of a ZL205A alloy after separate and combined addition were studied by conducting a fluidity test. The fluidity of the ZL205A alloy first increased and then decreased with the increasing addition of Al–Ti–C and La; it peaked at 0.3% and 0.1% for Al–Ti–C and La, respectively. The combined addition of Al–Ti–C and La led to better fluidity, which increased by 74% compared with the base alloy. The affecting mechanism was clarified through microstructure characterization and a DSC test. The heterogeneous nucleation aided by Al–Ti–C and La, the number of particles in the melt, and the evolution of the solidification range all played a role. Based on the evolution of the fluidity and grain size, the optimal levels of Al–Ti–C and La leading to both high fluidity and small grain size were identified.