TC21 titanium alloy was investigated. The samples were solution treated at 900°C for
15 min followed by cooling either/ water quenching (WQ) or air cooling (AC).
Consequently, aging treatment was applied at 575°C for 4 hr. The results showed that
heat-treatment parameters (cooling rate and aging treatment) had influenced the feature
and content of α phase, β phase and secondary α phase. Optimum heat treatment process
of TC21 titanium alloy was obtained by treatment at 900°C/ 15 min/ AC + 575°C/ 4 hr/
AC. Under this treatment condition, better combination of hardness and tensile
properties was achieved.