Effect of Grain Size, Grain Shape and Subgrain Size on High Temperature Creep Behaviour

  • G. Malakondaiah Defence Metallurgical Research Laboratory, Hyderabad
  • P. Rama Rao Defence Metallurgical Research Laboratory, Hyderabad
Keywords: Power law creep, Climb creep, Coble creep, Harper Dorn creep, Nabarro Herring, Polycrystal grain size

Abstract

Several strengthening machanisms, namely solute strengthening, precipitation and fine particle strengthening, grain size as well as shape control and substructure strengthening, have been utilised in the development of creep resistant alloys. Of these, the effect of polycrystal grain size, grain shape and subgrain size on viscous as well as power-law (climb) creep processes are considered here. Viscous creep processes include Nabarro-Herring (N-H), Coble and Harper-Dorn (H-D) creep. N-H and Coble creep processes are strongly influenced by grain size whereas creep rates under H-D creep are independent of grain size. Though it is usually assumed that power-law creep is independent of grain size, in practice it is not so. Several investigations have revealed that power-law creep does depend on grain size. There are detailed and well understood results pertaining to the role of grain size in viscous creep. On the other hand, subgrain size has been seen to have effect only on the climb creep behaviour which is yet to be clearly understood.

Author Biographies

G. Malakondaiah, Defence Metallurgical Research Laboratory, Hyderabad
Defence Metallurgical Research Laboratory, Hyderabad - 500258
P. Rama Rao, Defence Metallurgical Research Laboratory, Hyderabad
Defence Metallurgical Research Laboratory, Hyderabad
Published
2014-01-22
How to Cite
Malakondaiah, G., & Rao, P. (2014). Effect of Grain Size, Grain Shape and Subgrain Size on High Temperature Creep Behaviour. Defence Science Journal, 35(2), 201-217. https://doi.org/10.14429/dsj.35.6009
Section
Special Issue Papers