The Orowan mechnaism, which explains the hardening effect of precipitate particles when the participates have grown to a size where they are no longer coherent with the matrix, is shown in Fig. 16.17. The strengthening arises from the fact that the disloactions must bow out between two neighboring precipitate particles. This bowing out is opposed by the line of tension of the dislocations. Ashby has deduced an equation giving the stress needed to dislocations under conditions conforming to the Orowan model. An equation giving this stress, which assumes that the particles are spherical and that the system involves iron containing carbon, may be found in Leslie, W.C., The Physical Metallurgy of Steels, McGraw Hill Book Company, New York, 1980, p.198. It is:

Question

Answer 1