Effect of thermo-mechanical treatments on the structural properties and tribological behavior of precipitation hardenable Cu-4Ti (wt%) alloy

Cu-4Ti alloy was solution annealed at 900°C for 1 h and water-quenched followed by direct aging (variant I) or aging after 50 % cold rolling (variant II) at 450–600°C for 1–420 min. Microstructure, hardness and wear properties were studied. Variant I yielded uniform β'-Cu 4 Ti precipitates, reaching 240 HV after 120 min. at 500°C and narrowing wear tracks to 540 µm² with 4 µm penetration depths. Variant II attained 300 HV in 15 min, yet its dislocation-rich gradient microstructure promoted over-aging, β-Cu 3 Ti coarsening and partial recrystallization, expanding grooves beyond 1 mm² despite higher hardness. ANOVA confirmed temperature as dominant wear driver. Overall, variant I offers best hardness–wear compromise, whereas variant II provides only optimized short aging.