Microstructure regulation and mechanical properties of Ti3SiC2-derived network-structured TiC-Ti5Si3/TA1 composites

Titanium matrix composites (TMCs) with network-structured reinforcements offer a promising route to improving the strength–ductility balance. In this work, TiC-Ti 5 Si 3 /TA1 composites were fabricated by powder metallurgy and spark plasma sintering using Ti 3 SiC 2 as the precursor for the in situ formation of TiC and Ti 5 Si 3 . The effects of TA1 powder size, ball-milling time, and ball-milling speed on phase evolution, network formation, microstructure, and mechanical properties were systematically investigated. Ti 3 SiC 2 particles were mechanically embedded into TA1 powder surfaces during ball milling and subsequently reacted during sintering, producing TiC-rich regions along prior-powder boundaries. The 80-100 mesh TA1 powder favored the formation of a continuous TiC-rich network, whereas finer powders promoted a more dispersed reinforcement distribution. Appropriate milling conditions enhanced precursor embedding while preserving the original powder geometry, leading to continuous or quasi-continuous networks; excessive milling caused severe powder damage, disrupted the network template, and deteriorated tensile properties. The optimal tensile strength reached 778.72 MPa for the specimen milled at 300 rpm for 5 h, while the 200 rpm specimen exhibited a strength of 722.99 MPa with an apparent fracture strain of 24.74%. Semi-quantitative analysis indicated that Si solid-solution strengthening and grain-refinement strengthening were dominant, contributing 42.64% and 37.54% of the estimated strength increment, respectively, while TiC-network load transfer and Ti 5 Si 3 dispersion strengthening contributed 14.71% and 5.11%, respectively. The tensile response was governed by the combined effects of network continuity, defect population, interfacial stability, and retained deformable TA1 matrix domains. These results clarify the process–structure–property relationships in Ti 3 SiC 2 -derived network-structured titanium matrix composites and provide guidance for their microstructural design.