Effect of phase coarsening on the mechanical properties of alloys: II. Mechanism analysis

For alloys strengthened by precipitates, the precipitate size and distribution within the inner structure will change significantly during phase coarsening. Correspondingly the alloys will behave as different deformation and failure manners, and their mechanical properties will show a considerable variation. In this paper, we investigate in detail the variations of the mechanical properties of alloys with various microstructures, including the hardness, strength, ductility, and fracture toughness, etc., based on the deformation and failure characteristics under different deformation conditions. Especially we focus on the evolution of related internal variables in alloys and the mechanism analysis. Our analysis demonstrates that degradations for the mechanical properties of alloys during phase coarsening are sensitive to the change of their microstructures, i.e., the precipitate size and distribution in the alloys. The microstructural evolution in alloys alters the manners of the nucleation, multiplication, and movement of dislocations in the material, which further results in different macroscopic mechanical behaviors of alloys. The corresponding mechanism analysis is helpful for the design of material microstructure.