MICROSTRUCTURE AND TENSILE DEFORMATION OF REACTIVE-SINTERD TiAl(Mn) INTERMETALLICS

초록

A series of titanium aluminides having various microstructures is produced by reactive sintering under HIP. With the control of alloy composition and HIP condition, duplex structures(lamellar γ/α2 grain + equiaxed γgrain) having different lamellar volume fraction and a fully lamellar structure are abtained. Moreover, the grain size of a fully lamellar structure is considerably reduced by 2 vol% addition of TiB2 particulates. Both at room temperature and 1073K, the yield strength and U.T.S. tend to increase with increase in the volume fraction of lamellar grain, or with grain refinement of lamellar grain. The elongation is enhanced as the volume fraction of γgrain increase, or as lamellar grain is refined. All these results indicate that the suitable microstructure is a fully lamellar structure with an optimal(fine) grain size in considering the balance of ambient and elevated tensile properties