Post on 05-Apr-2022
Microstructure Control and Property Optimization
of High-strength Weldable Steels Strengthened by
Nanoparticles for Construction Applications
B.C. Zhou, M.C. Niu, Z.B. Jiao
Department of Mechanical Engineering
❖ High strength: nanoprecipitates with sizes of 1-5 nm are effective in
strengthening steels
❖ High ductility/toughness: strengthening without a significant reduction
of ductility and toughness
❖ Low material cost: less consumption of alloying elements
❖ Good weldability: low carbon content facilitates good weldability
❖ Easy to process: solutioning and aging treatment
Precipitation strengthening has been recognized as the most
effective method to strengthen steels.
Benefits of nanoprecipitation strengthening
7
Conclusions
➢ Through the partially replacement of expensive Ni and Co with
inexpensive Cr while optimizing the Ti and Mo concentrations, a new
class of ultrahigh strength steels was developed, which achieves
comparable mechanical properties as conventional maraging steels
but with a substantially reduced cost.
➢ The newly developed steels exhibit a yield strength of 1.8 GPa and a
ductility of more than 10%. Strength modeling indicates that the
strength increment originates mainly from the precipitation
strengthening of Ni3Ti, Mo-enriched, and Cr-rich particles.