Abstract: In situ self-forming core-shell reinforced A356 aluminum matrix composites were prepared by powder thixotropic forming technique. The effects of solid solution time on the microstructure and mechanical properties of Ti@(Al-Si-Ti)_p/A356 composite were investigated. The results show that, with the solution time increasing, the primary α-Al phase particles coarsen and grow. Eutectic Si phase is dissolved continuously, and the residual eutectic Si on grain boundaries is coarsened and spherical. Al matrix and Ti core continue to react and phase transition occurs in the enhanced granular shell.The mechanical properties of the composite reaches a peak at 545 ℃ solution treatment for 1 h, and their tensile strength, yield strength and elongation are 263.9 MPa, 175.1 MPa and 20%, respectively. Compared with the prepared composites,7.3%,21.4% and 12.4% are increased, respectively. The vickers hardness is also increased from 59.3 HV to 72.8 HV.