The hot deformation behavior of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy with equiaxed microstructure was characterized in the temperature range of 900～1060 ℃ and strain rate range of 10-3～10 s-1.The experimental results indicate that the plastic deformation behavior of the titanium alloys is rather sensitive to temperature and strain rate.In the α+β phase temperature region,all of the stress-strain curves exhibit different degrees of the flow softening after a peak stress.In the β phase temperature region,the titanium alloy shows a stress softening at high strain rates and a steady flow stress at low strain rates.On the basis of the peak stress data,the constitutive equations were constructed in the α+β phase temperature region and β phase temperature region,respectively.Activation energy parameters were calculated to be 344.923 kJ·mol-1 in the β phase temperature region and 628.3 kJ·mol-1 in the α+β phase temperature region.Microstructure of the compressed specimens in water-quenched conditions was found to be quite dependent on the conditions of deformation.
HUANG Lujun,GENG Lin,LI Aibin,WANG Guisong,and SHI Lei School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China
TC11 titanium alloy samples with lamellar microstructrue were compressed on a Gleeble 1500D Simulator.Compression tests were carried out at 950 ℃ and a strain rate of 0.1 s-1 with height reduction of 20%,40% and 60%,respectively.Microstruture of the compressed TC11 alloy was obeserved and analyzed by optical microscopy(OM),transmission electron microscope(TEM),electron back-scattered diffraction(EBSD).The lamellar disintegration mechanism of the TC11 titanium alloy was deduced.The results indicated that the compressive deformation promoted the phase transformation in bi-phase area.βphase layers were formed along the gliding planes inα phase,and α slivers were disintegrated into many small flakes through theα/βinterface slipping.
