Structural sensitivity of crack resistance of molybdenum at different temperatures

 
N.M.Marchenko,
 
G.Yu.Koval,
  

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Mathematical Models and Computing Experiment in Material Science - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2016, #18
http://www.materials.kiev.ua/article/2131

Abstract

The interaction of the dislocations emitted from the crack tip, with the grain boundary is analysed using dislocation dynamics method. The sharp growth of the fracture toughness is found, which happens at grain sizes approximately equal to the plastic zone size. It is shown that at large grain sizes the size of plastic zone has little effect on the fracture toughness. When dislocations reach the grain boundary, distribution of disclocations in the plastic zone changes, which leads to increase of the fracture toughness.


BRITTLE-DUCTILE TRANSITION, DISLOCATION ENSEMBLE, FRACTURE TOUGHNESS FACTOR, GRAIN SIZE