Phase-field simulation of multilayer microstructure of Cr-enriched phase induced by alternating strain

Strain-induced microstructures have special effects on the mechanical properties of alloys. Alternating tensile/compressive strains can produce multilayered strain distributions inside the alloys, the microstructure and elements of the nanoscale precipitates will be redistributed. It is the first attempt to reveal the effects of alternating strain on the morphology and composition evolution of the nanoscale phase by utilizing phase-field simulation. When the tensile/compressive strains are applied in the multilayer alloy with different magnitudes and orders, the solute atoms gather in a preferential model to the boundary which in relaxed strain state, forming the band shape morphology parallel to the boundary. Nanoscale lamellar structure of alternating precipitation/matrix is formed in the three dimensional space. When the layer width is small enough, the precipitation bands of boundary undergo coalescence into a lamellar by the diffusion of Cr atoms in the tensile strain regions, while the compressive strain regions become matrix layer. This study provides a better known of formation of nanoscale lamellar microstructure with the nanoscale phase evolution in iron-based alloys under alternating strain.