The role of interphase boundary phenomena on mechanical behavior during high-temperature deformation

The influence of interphase boundary on the mechanical behavior of a two-phase (α/β) Ni-Modified Ti-6A1-4V alloy during superplastic deformation (SPD), has been investigated in the range of temperature and strain rate where maximum ductility is - attained.Uniaxial tests for constant and differential strain rates were performed over the - range of 5.0 x 10-5 s-1 to 5.0 x 10-3 s-1 and at temperature from 1023 to 1123 K. To optimize the initial microstructure, tensile specimens were static annealed in argon for 1 hour at 815 °C ( SA-1-815).Upon completion of the tests, specimens were quenched in pre-chilled argon to pre—serve the high temperature microstructure for metallographic analysis. The gage portion of the specimen was polished and etched in a solution of 2 ml HF, 3 ml HNO3 and 95 ml H2O. Subsequently, they were subjected to scanning and transmission electron - microscopy (SEM and TEM) examination. A Quantimet Image Analizer was used for determining the phase size, its distribution and volume fractions.