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The formation of nanoscale precipitates influences the uniform mechanical properties of steels. The precipitation behavior in a Ti‐bearing steel with 50% hot deformation is investigated at different continuous cooling rates, including 0.5, 2, and 5 °C s−1. It is found that both the random precipitation and the interphase precipitation are observed in the hot deformed steel by means of transmission electron microscopy (TEM). At the cooling rate of 0.5 and 2 °C s−1, the interphase precipitation and the random precipitation occur even in the same ferrite grain. When the cooling rate is 5 °C s−1, the interphase precipitation disappears and only the random precipitates exist in the small ferrite grains. The morphologies of the interphase precipitation change from the irregular curved type (I‐CIP) to regular curved type (R‐CIP), and finally to the regular planar type (PIP) with the increase of the cooling rate. The interphase precipitation adjacent to the ferrite grain boundaries reveals its preferential occurrence in the final stage of the transformation. Compared with the isothermal heat treatment, the control of precipitation behavior via cooling rate adjustment is easier and less time‐consuming to obtain tailored mechanical properties of the steel. [ABSTRACT FROM AUTHOR]

In the present work, the atomic interactions among Cu, Al, and Ni elements in body‐centered cubic (BCC) ‐iron matrix, focusing on the formation mechanism of nano‐sized core–shell Cu precipitates, are investigated. In this study, using a combination of atom probe tomography, density‐functional theory (DFT) calculations, and molecular dynamics simulations, insights into the atomic‐scale migration tendencies of these elements in the supersaturated solid solution surrounding Cu precipitate in the martensite phase of a medium‐Mn steel are provided. In the results, it is shown that Ni and Al atoms are not expelled by Cu atoms but are instead attracted to the bcc‐iron matrix, forming a stable co‐segregation in the outer shell. This phase effectively surrounds the nano‐sized Cu precipitate and prevents its rapid growth, contributing to improved mechanical properties. In these findings, a theoretical method is offered for developing Cu‐contaminated circular steels by utilizing DFT calculations to unravel bonding preferences and assess the potential for forming a stable precipitation phase around nano‐sized Cu precipitates. [ABSTRACT FROM AUTHOR]

A Fe–Al–Mn–Ni–C steel is designed explicitly to precipitate intermetallic phases in specific phases of a duplex steel. CALPHAD‐assisted alloy design is carried out with respect to an innovative "solublility‐assisted precipitation" (SAP) mechanism. A four phase equilibrium comprising of ferrite, austenite, κ‐phase (Fe3AlC), and B2‐phase (NiAl) is stabilized in a suitable annealing window. The processing conditions are adjusted according to elemental partitioning and consequential stabilization of κ‐phase in austenite and B2‐phase in ferrite. The feasibility of the SAP mechanism is validated by investigation of microstructure and precipitation evolution using electron microscopy and site‐specific atom probe tomography. A concept to direct precipitation of intermetallic phases to specific phases of a high‐Al alloyed duplex steel is proposed. CALPHAD‐assisted alloy and processing design is carried out to control elemental partitioning and facilitate the formation of intermetallic precipitates. A validation of the proposed concept is conducted by a multi‐scale experimental characterization using electron microscopy and atom probe tomography. [ABSTRACT FROM AUTHOR]