[en] This lecture focuses on an overall review of the physics and mechanics of ductility and ductile fracture of two-phase alloys. Experimentally observed ductile fracture processes are examined first. In the absence of void-nucleating non-metallic second-phase small particles, a single crystal of some metals within a suitable temperature range may be drawn to a chisel point in a tensile test. A similar phenomenon can be produced in some polycrystalline metals under hyrostatic pressure which retards the formation and growth of microvoids at second-phase non-metallic particles. Hence, it is believed that ductility is highly affected by the presence of void-nucleating particles. Voids are usually nucleated by either the cracking of particles (weak, brittle particles) or by the decohesion of the particle matrix interface (for strong particles), so that ductility increases of the particle strength and the interfacial bond are increased. Moreover, voids are first nucleated at larger particles, and therefore ductility tends to increase with decreasing particle size and volume fraction of void-nucleating particles. Analytical and numerical methods used to analyze the above-mentioned processes are discussed next. Early work in this connection considers noninteracting voids of special geometry. Nevertheless, it has been demonstrated analytically that the stress triaxiality may influence ductility to a large extent. Such a state occurs naturally in front of a blunted microcrack in metals, in a necked tensile test bar, or immediately upon loading in notched tensile test bar. Recently, several attempts have been made to include the void-interaction effects by numerical analysis