Tailoring co-precipitation behavior by molybdenum microalloying in high-strength steels

The precipitation behavior of co-precipitates including Cu-rich precipitates (CRPs) and Ni(Al, Mn) particles and the hardness of the molybdenum microalloying high-strength steels were carefully investigated. It was found that individual additions of Mo atoms gave rise to an obvious hardness effect compared with the carbides precipitation steels. Although Mo atoms were primarily partitioned within the matrix rather than within the coprecipitates, the nucleation/growth process of co-precipitates was accelerated due to reducing the misfit strains between matrix and precipitates. Moreover, with increasing Mo microalloying, the coarsening of coprecipitates was retarded owing to the reducing coarsening coefficients of co-precipitates. The hardness peak time was shortened and the hardness plateau were prolonged by the precipitation of co-precipitates, showing potential high thermostability of Mo microalloying steels.

Automated summary

The addition of Mo atoms can significantly increase the hardness effect of high-strength steels, while also slowing down the coarsening process of co-precipitates, demonstrating potential high thermostability.