Complex Precipitation Pathways in Multi-Component Alloys

摘要: One usual way to strengthen a metal is add alloying elements and control the size density of precipitates obtained. However, precipitation in multicomponent alloys can take complex pathways depending on relative diffusivity solute atoms driving forces involved. In Al-Zr-Sc alloys, atomic simulations based first-principle calculations combined with various complementary experimental approaches working at different scales reveal strongly inhomogeneous structure precipitates: owing much faster Sc compared Zr solid solution, absence diffusion inside precipitates, precipitate core mostly Sc-rich, whereas external shell Zr-rich. This explains previous observations an enhanced nucleation rate binary Al-Sc along higher resistance Ostwald ripening, two features utmost importance field light high-strength materials.