ABSTRACT
Second phase particles occur as a result of their thermodynamic stability, and their distribution and morphologies may also be affected by the thermal and thermomechanical treatments given, and by the alloy design. As described in the previous chapter, the volume fraction of particles, their location, and the size of the particles, are important with respect to the control of grain size. In this chapter, therefore, the thermodynamic and alloy design aspects will be considered, and a brief description of the formation of the second phase particles will be given. Because of the importance of particle size, the particle growth process, known generally as Ostwald ripening, will also be considered. The type of particle, and the alloy chemistry, can have important effects on the stability of the particles at elevated temperatures, and on the particle coarsening rates, as will be shown.
