Hardness and microstructure changes in severely deformed and recrystallized tantalum Conference Paper uri icon


  • Vacuum arc remelted (VAR) pure tantalum was deformed at room temperature to a strain of 4.6 by multipass equal channel angular extrusion through a tool containing an abrupt 90 degree angle. The as-worked microstructure shows a progression from dense dislocation tangles containing primitive dislocation cells at a strain of 1.2, to the development of well defined subgrains with dimensions on the order of hundreds of nanometers at a strain of 4.6. The recrystallization temperature decreases from about 1100°C to 900°C as the strain increases from 1.2 to 4.6. The recrystallized grain size for the material strained to 4.6 is under 15 microns. The Hall-Petch relationship is found to reasonably predict subgrain size from microhardness measurements in the most severely deformed material.

author list (cited authors)

  • Hartwig, K. T., Mathaudhu, S. N., Maier, H. J., & Karaman, I.

publication date

  • January 2002