Effect of strain rate and temperature on the deformation behavior in a Ti-23.1Nb-2.0Zr-1.0O titanium alloy

摘要

The compression behavior of a Ti-23.1 Nb-2.0 Zr-1.00(at.%)alloy was investigated at strain rates from 0.1 s_(-1) to 1000 s_(-1) and temperatures from 100℃to 200℃on a Gleeble 3800 system and Split Hopkinson Pressure Bar(SHPB)compressive tester.Optical microscopy,electron backscatter diffraction(EBSD),Xray diffraction(XRD)and transmission electron microscopy(TEM)were employed to characterize the microstructure evolution during the deformation.Numerous deformation phenomena,including dislocation slip,twinning of both{332}{113)and{112}{111}modes,stress-inducedα"martensite(SIMα")and stress-inducedω(SIω)transformations,were observed.The preferred activation of twinning and SIωtransfo rmations was observed in the sample compressed at lower temperatures and/or higher strain rates.The underlying mechanism is that twinning and stress induced phase transfo rmations are attribute to higher stress concentrations atβgrain boundaries and additional energy supplied by a higher strain rate,as well as high stacking fault energy because of higher temperature.