Microstructure Evolution of Inertia Friction Welded Joints of TC21 Titanium Alloy

In this paper, TC21 titanium alloy welded joints were successfully formed through inertial friction welding (IFW) processes. Microstructure evolution of IFW was investigated by way different analysis methods including optical microscope (OM), scanning electron microscope(SEM), Electron Back-Scattered Diffraction(EBSD), X-Ray Diffraction(XRD), and Energy Dispersive Spectrometer(EDS). The results indicate that large-sized equiaxial ? grains, original ? phases, basketweave structure existing in the BM have completely disappeared WZ. Instead, fine grains sized at 20–30 ?m very + lamellar microstructure are However, as transition zones, microstructures TMAZ HAZ also state while partially remain HAZ. addition, second phases precipitated on base XRD EBSD reveal proportion phase WZ zone decreases greatly. EDS show there aggregations stabilizing elements BM, but no element aggregation Dynamic recrystallization during process distribution under rapid cooling condition after believed to be responsible for formation weld joints.