The presentation provides data on structure of the in-situ Ti-TiB discontinuously reinforced composites, namely Ti-1.6-wt.% B; Ti-5.5Al-1.9B, and Ti-6.6Al-3.5Zr-1.2Si-1.1B, and their fracture mechanisms and mechanical properties. Composites were produced with casting technology. The mechanical properties of the in-situ composites were established at tension and bending at room temperature and 600-700 degreesC. Young's modulus of deformed composites with randomly oriented TiB needles was 136 GPa in Ti-1.6B alloy; Ti-5.5Al-1.9B alloy gives 152 GPa. Joint reinforcement of titanium with borides and silicides in the Ti-6.6Al-3.5Zr-1.2Si-1.1B alloy enhances Young's modulus to 158 GPa at 1530 MPa strength. All the composites demonstrate ductile behavior at room temperature ensuring high potential of plasticity.