Influence of hydrogen content on hot deformation behavior and microstructural evolution of Ti600 alloy

Abstract

Isothermal hot compression tests of a Ti600 alloy after hydrogenation were carried out over the temperature range of 760 to 880℃ and strain rate range of 0.01 to 10 s-1. The influence of hydrogen content was studied on the flow stress and activation energy of deformation. The microstructural changes were examined by transmission electron microscopy (TEM). The results show that the addition of 0.3% hydrogen in Ti600 alloy can decrease the hot deformation temperature by 80 •C and increase the deformation strain rate by two orders of magnitude. Both the flow stress and activation energy of deformation of Ti600 alloy decrease gradually with increasing hydrogen content in the hydrogen range of 0 to 0.3%. TEM observation suggests that dynamic recrystallization (DRX) is promoted after hydrogenation. Hydrides δ (fcc structure) exist in the specimens with 0.3% and 0.5% hydrogen, and the hydrides tend to be broken up and twisted with increasing hydrogen content after deformation. The mechanism of hydrogen reduced flow stress of Ti600 alloy has been discussed in detail. Isothermal hot compression tests of a Ti600 alloy after hydrogenation were carried out over the temperature range of 760 to 880• C and strain rate range of 0.01 to 10 s −1 . The influence of hydrogen content was studied on the flow stress and activation energy of deformation. The microstructural changes were examined by transmission electron microscopy (TEM). The results show that the addition of 0.3% hydrogen in Ti600 alloy can decrease the hot deformation temperature by 80• C and increase the deformation strain rate by two orders of magnitude. Both the flow stress and activation energy of deformation of Ti600 alloy decrease gradually with increasing hydrogen content in the hydrogen range of 0 to 0.3%. TEM observation suggests that dynamic recrystallization (DRX) is promoted after hydrogenation. Hydrides ı (fcc structure) exist in the specimens with 0.3% and 0.5% hydrogen, and the hydrides tend to be broken up and twisted with increasing hydrogen content after deformation. The mechanism of hydrogen reduced flow stress of Ti600 alloy has been discussed in detail.

Hot Deformation Behavior and Microstructure Evolution of a TiBw/Near α-Ti Composite with Fine Matrix Microstructure

“…The spheroidization of secondary α phase is more obvious. Furthermore, as the strain rate increases, the proportion of β t increases with strain rate, which is ascribed to the adiabatic temperature rising caused by the low thermal conductivity of titanium during the high strain rate deformation [33]. TEM micrographs are shown in Figure 10 to investigate the effect of the strain rate on the evolution of matrix microstructure.…”

Research on the hot deformation behavior of Al–6.2Zn–0.70Mg–0.3Mn–0.17Zr alloy using processing map

“…The Zener-Hollomon parameter, as a temperature compensated strain rate factor, can be used to describe the combined effects of temperature and strain rate on the hot deformation process [26,27]. The expression of material's hot deformation behavior represented by the Z parameter is obtained as: Table 4.…”

Recent developments in plastic forming technology of titanium alloys

“…In refs. [84][85][86][87], the effect of THP on the hot working of Ti600 (Ti-6Al-2.8Sn-4Zr-0.5Mo-0.4Si-0.1Y) was investigated. It was found that the flow stress could be greatly reduced within hydrogen content range of 0.1-0.3wt%.…”