Role of diffusional coherency strain theory in the discontinuous precipitation in Mg–Al alloy

[摘要] Discontinuous precipitation (DP) occurs in many alloy systems under certain conditions. It is called discontinuous precipitation because precipitation occurs on prior matrix grain boundaries followed by grain boundary movement. The DP nodule consists of alternate lamellae of the precipitate and the matrix respectively. The chemical driving force for DP is one of solute supersaturation. Although solute supersaturation is responsible for precipitation, it has to be coupled with another driving force to explain grain boundary migration. This coupling driving force has been identified to be diffusional coherency strain which has been verified to be active in diffusion induced grain boundary migration and liquid film migration.

[学科分类] 材料工程

[关键词] DP;Mg–Al alloy;Mg–7Al–1Pb alloy;DIGM;LFM.