Microstructure characterization and mechanical properties of in situ synthesized Ti2(Al,Si)C reinforced Al composites

A novel composite with in situ synthesized of Ti2(Al,Si)C solid solution reinforced Al matrix was fabricated in Ti2AlC-Al-Si material system via one-step solid solution and densification by spark plasma sintering method. The relationship between microstructure, phase composition and mechanical properties of composites doped with different Si content (1, 2 and 3 wt%) and fabricated at different sintering temperature (580, 570 and 560 degrees C) were investigated. The optimal sintering temperature of composites with increasing the Si addition was carefully determined. The interface reaction was effectively regulated under different Si additions. X-ray photoelectron spectroscopy (XPS) and nanoindentation test results reveal that Si formed Si-C covalent bond in Ti2(Al,Si)C solid solution, and with the increase of Si addition, the hardness and elastic modulus of Ti2(Al,Si)C increased by 6.75% and 4.23% in the composites prepared by the three optimal processes. The tensile tests show that when the addition of Si was 2 wt% and the sintering temperature was 570 degrees C, the composites demonstrated an optimal balance of strength and plasticity. The ultimate tensile strength reached 226 MPa with a strain of 14.33%. Moreover, when added to 3 wt% and the sintering temperature decreased to 560 degrees C, the composite achieved a significant improvement in elongation. The performance are mainly attributed to the strengthening of Ti2(Al,Si)C solid solution and the regulation of interface reaction.

Automated summary

A novel composite with in situ synthesized of Ti2(Al,Si)C solid solution reinforced Al matrix was fabricated via one-step solid solution and densification method. The relationship between microstructure, phase composition and mechanical properties of the composites doped with different Si content and fabricated at different sintering temperature was investigated. The results showed that introducing Si can enhance the hardness and elastic modulus of the composites, and an optimal balance of strength and plasticity can be achieved when the Si content is 2 wt% and the sintering temperature is 570 degrees C.