EFFECT OF HOT DEFORMATION ON STRUCTURE FORMATION AND PROPERTIES OF SEMIPRODUCTS FROM TITANIUM ALLOY Ti - 10 percent V - 2 percent Fe - 3 percent Al

摘要

Preliminary forging of alloy Ti -10 percent V- 2 percent Fe - 3 percent Al in the #beta#-region promotes crushing of the grain structure and formation of a more disperse #alpha#-phase in the process of subsequent deformation in the (#alpha#+#beta#)-region. This has a favorable effect on the mechanical properties of the alloy. Intensification of the deformation in the #beta#-region creates pre-requisites for a quite uniform segregation of the primary #alpha#-phase, which increases the ductility of the alloy after deformation in the (#alpha# + #beta#)-region with the same degree. The increase in #epsilon#_(#alpha#+#beta#) can cause a certain strengthening of the alloy due to strain-induced hardening of the #beta#-matrix.In order to provide high ductility, strength, and impact toughness in alloy Ti - 10 percent V - 2 percent Fe - 3 percent Al in a thermally hardened state we should provide a polygonized structure rather than a recrystallized one in deformation in the #beta#-and (#alpha# + #beta#)-region, which makes the segregation of the #alpha#-phase more uniform. Such a structure forms in the alloy if #epsilon#_#beta#>=50 percent and #epsilon#_(#alpha#+#beta#)>=50 percent.The set of properties in alloy Ti - 10 percent V - 2 percent Fe -3 percent Al is optimum after deformation with #epsilon#_#beta# >= 50 percent, #epsilon#_(#alpha#+#beta#)>=50 percent, and subsequent heat treatment, namely, #sigma#_(0.2) = 1300 MPa, #sigma#_r = 1355 MPa, #delta#= 10 percent, #psi# = 25 percent, KCT= 0.81 MJ/m~2.