The mechanical properties of Ti-Cu alloys processed via thixoforming were evaluated. Ti-Cu (25, 27, and 29 wt.% Cu) ingots were produced via arc melting, homogenization at 950 °C for 24 h, and hot-forging at 900 °C, followed by thixoforming at a speed of 8 mm/s after isothermal heat treatment at 1035 °C for 300 s. The thixoformed alloys exhibited good mechanical strength, limited plasticity under tensile loading, and reasonable plasticity under compressive loading. The mechanical strength and plasticity decreased as the Cu content increased as a result of the increasing volume fraction of the peritectic Ti₂Cu phase (transformed liquid), which exhibited a lower strength and plasticity than the α + Ti₂Cu regions (transformed solid). These findings indicated that the trade-off between the mechanical properties and semisolid processability is largely governed by the Cu content.