A Bridge Between NDE and Charpy Impact Testing

Charpy impact test is explained from the viewpoint of the transition of hammer's energy to the kinetic energy of dislocations. Ductile-brittle transition temperature theta is represented as a simple function of the nucleation energy of dislocations epsilon(n), the dislocation density rho, the maximum density of mobile dislocations rho(o) and the interaction energy of obstacles with dislocations U-ob; k theta = U-ob rho(o) +(rho(o)-rho)epsilon(n) when rho < rho(o), while k theta = U-ob rho(m) when rho > rho(o), where k is Boltzmann constant and rho(m) is the density of mobile dislocations. The relationship is compared with the experimental results for cold rolled S15C steels and neutron irradiated low and high copper A533B steels of nuclear reactor pressure vessel materials. The experimental results are qualitatively explained by the present model.