In-situ high modulus steel strengthened with Ni3Ti nano-precipitation

Abstract

The low yield strength of high modulus steels (HMSs) hampers their practical applications as high-rigid structural materials in key sectors such as construction and transportation. To address this challenge, we introduce a small amount of nickel into the Fe-Ti-B alloy system, leveraging the strengthening concept of maraging steels without significantly increasing alloying costs. The resulting Ni-added HMS, in its as-hot-rolled state and reinforced with TiB₂, contains dense Ni₃Ti nanoprecipitates within the ferrite matrix. These nanoprecipitates effectively shorten dislocation segments, thereby increasing the flow stress required for the continuous dislocation movement. Meanwhile, this new HMS maintains a high Young's modulus and low density, comparable to existing Fe-TiB₂ steel. This work offers a viable approach to producing cost-effective high modulus steels with enhanced strength levels suitable for structural applications.