Observations on the compression properties of semisolid Ti–Cu alloys

Abstract

Ti–Cu alloys are considered viable candidates for thixoforming (semisolid processing) due to their solid–to–liquid transitions and good microstructural properties. In the present study, the deformation behavior of these alloys in the semisolid state has been investigated by performing hot compression tests on Ti–(25, 27, 29)Cu samples isothermally treated at 1035 °C for 300 s. In general, relatively low loads were applied to deform samples with globular microstructure, which decreased with increasing liquid fraction (Cu content). In contrast, dendritic samples required much higher loads; the resulting materials were significantly more heterogeneous and contained large numbers of microstructural defects. At applied compression velocities of 4, 8, and 16 mm s−1, the strain rate had little effect on the response of the globular material; however, longer isothermal heat treatments significantly reduced the compression load due to globularization enhancement. The obtained results suggest potential applicability of Ti–Cu alloys for semisolid processing.

Keywords

• Semisolid processing
• Thixoforming
• Ti alloys
• Compression tests
• Microstructure