TITLE:
Effect of Heat Treatment Processes on Microstructure and Mechanical Behavior of TC21 Titanium Alloy
AUTHORS:
Ramadan N. Elshaer, Khaled M. Ibrahim, Azza F. Barakat, Reham R. Abbas
KEYWORDS:
TC21 Ti-Alloy, Cooling Rate, Aging, Microstructure, Tensile Properties, Wear
JOURNAL NAME:
Open Journal of Metal,
Vol.7 No.3,
August
31,
2017
ABSTRACT:
The effect of heat treatment on microstructure and tensile properties as well
as wear behavior on TC21 (Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-Si, wt.%) Ti-alloy
was investigated. The samples were solution treated at 900°C for 15 min followed
by furnace cooling to 800°C with a cooling rate 1°C/min and holding
for 20 min, then the samples cooled down to room temperature either using
water quenching (WQ) or air cooling (AC). Consequently, aging treatment
was applied at 575°C for 4 hr. The microstructure feature showed a secondary α phase (αs) precipitated in residual β phase due to the step cooling from
900°C to 800°C inside furnace as well as the aging treatment. The highest
wear rate was obtained for WQ samples due to increasing in volume fraction
of αp (58%). However, the lowest wear rate was reported for WQ + Aging
samples due to the high hardness. Optimum mechanical properties of the studied
TC21 Ti-alloy were obtained for AC + Aging condition. A better combination
of hardness, tensile properties, and wear resistance was achieved for
AC + Aging samples, although their wear resistance was found to be slightly
lower than that of WQ + Aging samples.