The Strain Hardening Behavior of TZAV 30 Alloy After Various Heat Treatments
Abstract The Ti Zr Al V series titanium alloys with excellent mechanical properties and low density exhibit tremendous application potential as structural materials in aviation, automotive, and navigation industries. The strain hardening behavior of Ti 30Zr 5Al 3V (wt. TZAV 30) alloy with various heat treatments is investigated in this study. Experimental results show that strain hardening behavior of the examined alloy depends on the heat treatment process. The average strain hardening exponent, n, is approximately 0.061 for WA specimen (825 degC/0.5 h/water quenching 600 degC/4 h/air cooling) 0.068 for FC (850 degC/0.5 h/furnace cooling) 0.121 for AC (850 degC/0.5 h/air cooling) and 0.412 for WQ (850 degC/0.5 h/water quenching) Analysis of strain hardening rate versus true strain curves indicates that higher n of AC specimen results from the lower degradation rate of strain hardening rate with strain, and the ultrahigh n of WQ specimen is attributed to the evident increase in strain hardening rate at the true strain from 0.04 to 0.06. Phase constitution and microstructural analyses reveal that the n of the examined alloy with a b phases increases with the increase in the relative content of the retained b phase but is independent of average thickness of a plates. The increase in strain hardening rate in WQ specimen depends on metastable a' martensite and martensitic transition induced by tensile stress.
Journal of Materials Engineering and Performance