EFFECT OF THE KIND OF MONOTONE LOADING ON THE TRANSFORMATION OF LAMELLAR MICROSTRUCTURE INTO A MICRODUPLEX ONE IN TITANIUM ALLOY VT9

摘要

The process of transformation of a lamellar microstructure into an equiaxial one in binary titanium alloys is determined not only by the temperature and rate conditions of the deformation but also by the kind of loading. The present work describes an experimental study of the effect of one- and two-component monotone loading on the microstructure and mechanical properties of binary titanium alloy VT9. It is shown that in two-component proportional loading the treansformation of the lamellar microstructure occurs more uniformly over the cross section and the length of the specimens than under simple twisting or uniaxial stretching. Subsequent deformation by uniaxial stretching under optimum temperature and rate conditions of superplasticity is characterized by diminished yield stresses and completion of the process of transformation of the initial microstructure in the entire volume of the speciments.