Microstructure and superior mechanical property of in situ (TiBw + TiCp)/Ti composites with laminated structure

The strength and ductility of titanium matrix composites (TMCs) hardly co-exist and show a trade-off between each other. In order to balance the strength and ductility of TMCs, in situ TiB whiskers (TiBw) and TiC particles (TiCp) strengthened Ti composites with laminated structure were constructed via electrophoretic depositing (EPD) boron (B) powders + graphene oxides (GOs) on pure Ti foils followed by spark plasma sintering (SPS). The experiment results reveal that increasing EPD duration leads to more synthesized TiBw + TiCp reinforcements accompanied by decreased grain size of Ti matrix in the sintered composites, which favorably results in gradually enhanced strength. A maximum yield strength (YS) of 569 MPa is achieved in the laminated composite, which is 75.6% higher than that of pure Ti sample (YS: 324 MPa). Meanwhile, the composite still owns a relatively higher elongation of 12.0%. The achievement of good ductility should benefit from the laminated architecture which exerts constraint effect on crack propagation. This work provides a short cut to achieve strength-ductility synergy in TMCs.