The grain boundary segregation behavior of Ti14, a new typical α+Ti2Cu alloy, was investigated after semi-solid forging at different temperatures. The results reveal that Cu is segregated in grain boundary during semi-solid deformation and precipitated as Ti2Cu phase during the solidification. Temperature has effects on the microstructures of precipitates. A nucleation and precipitation model of Ti2Cu was raised to express the processing of nucleation and precipitation, which can be explained by a nonclassical nucleation and growth theory.