Microstructure, Texture, Tensile Flow and Work Hardening Behavior of Tungsten Heavy Alloys in Swaged and Swaged plus Aged Conditions

摘要

Present work describes the development of microstructure, texture, tensile flow and work hardening behavior of tungsten heavy alloys in swaged and swaged + aged conditions. The microstructural attributes of both the alloys such as the average W-grain size, shape, volume fractions of matrix phase and contiguity are nearly same in swaged and swaged + aged conditions. The textures of W-grains and matrix are different in swaged and swaged + aged alloys. The overall ODF intensities of W-grains and matrix phase are moderate and weak, respectively. Both the alloys show higher strength and slightly lower elongation after aging of the swaged samples. The aging has significantly reduced the impact toughness values of both the alloys in swaged condition. The true stress-true strain plots of both the alloys in swaged and swaged + aged conditions exhibit continuous increase in stress from sigma(YS)to sigma(UTS)(except yield point phenomenon in swaged + aged samples). Both the alloys in swaged + aged condition reveal the presence of yield point phenomenon. Bulk hardness values of both the alloys increase from swage to swaged + aged conditions. The true stress-true plastic strain curves on log-log scale of both the alloys in swaged and swaged + aged conditions display single slope only and follow Swift constitutive equation due to presence of pre-strain in the materials. The overall nature of the instantaneous curves is same in swaged and swaged + aged conditions. These curves exhibit three distinctive regimes of strain hardening that are stage I, stage II and stage III. The linear part of stage III has been explained using KME model in both alloys.