Isothermal compression testing of Ti-10V-2Fe-3Al in (alpha + 8) phase zone was carried out. Hot compression flow stress curves have been determined, and changing laws of flow stress and microstructure versus temperature and strain rate have been discussed in order to provide test basis for determining isothermal forming technological parameters. The results show that flow stress is very sensitive to strain rates. For example, flow stress is 220 MPa for true starting strain rate of 1.0 s(-1) at 760degreesC, and, flow stress is only 40 MPa when strain rate is reduced to 1.6 x 10(-4)s(-1); it is reduced by 5.5 times. The effect of the deformation temperature on flow stress is relative with measure of strain rate. When deformation temperature increases from 760degreesC to 800degreesC, the flow stress decreases by 40 MPa using faster strain rate of 1.0s(-1), and decreases only by 10MPa using slower strain rate of 1.6 x 10(-4)s(-1). The observation results of microstructure show that at same deformation temperature the microstructure of Ti-10V-2Fe-3Al is finer and more uniform using faster strain rate than that of the primary a phase using slow strain rate. Under good forming condition of forgings, strain rate may be appropriately raised during isothermal forging of Ti-10V-2Fe-3Al.
