DUCTILE-BRITTLE TRANSITION IN THE REFRACTORY METALS

摘要

Transition temperature can be greatly influenced by testing and ma?terial conditions. As a general rule, the following factors increase the temperature at which the brittle transition occurs:n(1) Re crystallizationn(2) Decreasing amounts of cold workn(3) Increasing grain sizen(4) Increasing interstitial contentn(5) Increasing strain raten(6) Introduction of triaxial stresses.nThe transition from ductile to brittle behavior is associated with a rapid rise in yield strength occurring with reductions in temperature. Brittle behavior is observed to occur when the yield strength equals the fracture strength.Cottrell's theory of dislocation locking by interstitial atoms is generally used to explain the yield-strength rise at low temperatures.