Microstructure and properties of in situ TiCP/Mn18Cr2 architecture composites

Abstract

In situ TiC ceramic particle-reinforced steel matrix composites, typically produced via liquid metal infiltration of unstructured preforms, often demonstrate issues with composite areas being prone to fracture. To address this problem, particles with an average diameter of 3 mm were constructed and used to fabricate preforms. Using the in situ self-generation method, the composites were then synthesised with liquid Mn18Cr2. To control the degree of in situ spontaneous reaction, moderator alloy powders at concentrations of 20, 30, 40 and 50 wt.% were utilised. The results reveal that the TiC particle size in the composites gradually decreases as the moderator concentration in the preform increases, reducing from 1.31 to 0.92 μm. The microhardness and elastic modulus at the composite interfaces are intermediate between those of the TiC ceramic particles and the high manganese steel matrix. The inclusion of millimetre-scale architecture enhances the tensile strength of the composites, with tensile strength gradually increasing as the moderator content decreases. This study offers a comprehensive understanding of how moderator content influences the microstructure and mechanical properties of TiC-reinforced Mn18Cr2 composites, providing valuable insights for the development of high-performance structural materials.