TY - JOUR
T1 - Synergistic alloying effects on nanoscale precipitation and mechanical properties of ultrahigh-strength steels strengthened by Ni3Ti, Mo-enriched, and Cr-rich co-precipitates
AU - Niu, M. C.
AU - Yin, L. C.
AU - Yang, K.
AU - Luan, J. H.
AU - Wang, W.
AU - Jiao, Z. B.
N1 - Funding Information:
Z.B.J. acknowledges the financial support from the National Natural Science Foundation of China (51801169), State Key Laboratory for Advanced Metals and Materials Open Fund (2017-ZD01), Guangzhou International Science & Technology Cooperation Program (201907010026), and Chinese National Engineering Research Centre for Steel Construction (Hong Kong Branch) at PolyU (P0013862). W.W. acknowledges the financial support from the Youth Innovation Promotion Association of Chinese Academy of Sciences (2017233), the Innovation Project of Institute of Metal Research (2015-ZD04), the National Natural Science Foundation of China Research Fund for International Young Scientists (No. 51750110515), and the National Natural Science Foundation of China (No. 51472249). The theoretical calculations in this work were performed on TianHe-1(A) at National Supercomputer Center in Tianjin and Tianhe-2 at National Supercomputer Center in Guangzhou.
Publisher Copyright:
© 2021 Acta Materialia Inc.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5/1
Y1 - 2021/5/1
N2 - The synergistic effects of Mo, Ti, and Cr on nanoscale precipitation and mechanical properties of maraging stainless steels were systematically studied using high-resolution scanning transmission electron microscopy, atom probe tomography (APT), thermodynamic and first-principles calculations, and mechanical tests. Our results reveal a notable precipitation pathway involving the co-precipitation of Ni3Ti, Mo-enriched, and Cr-rich precipitates; their formations are not separated, but rather highly interacted. The APT results indicate that Mo partitions to the Ni3Ti precipitate core in the early stage of precipitation, which doubles the number density of Ni3Ti precipitates. Our calculations indicate that the Mo partitioning not only increases the chemical driving force, but also reduces the strain energy for nucleation, thereby accelerating Ni3Ti precipitation. As the precipitation proceeds, Mo atoms are rejected from the Ni3Ti precipitate core to the interface between the Ni3Ti precipitates and matrix, which leads to the heterogeneous nucleation of Mo-enriched precipitates on the outer surface of the Ni3Ti precipitates. This results in a substantial size refinement of Mo-enriched precipitates. In addition, the formation of Ni3Ti precipitates consumes Ni from the matrix, which substantially inhibits the spinodal decomposition and refines the size of Cr-rich precipitates. The cooperative strengthening of Ni3Ti, Mo-enriched, and Cr-rich co-precipitates leads to the development of new steels with a strength of 1.8 GPa; the contributions of these precipitates to the strengthening were quantitatively evaluated in terms of precipitate shearing and Orowan dislocation looping mechanisms.
AB - The synergistic effects of Mo, Ti, and Cr on nanoscale precipitation and mechanical properties of maraging stainless steels were systematically studied using high-resolution scanning transmission electron microscopy, atom probe tomography (APT), thermodynamic and first-principles calculations, and mechanical tests. Our results reveal a notable precipitation pathway involving the co-precipitation of Ni3Ti, Mo-enriched, and Cr-rich precipitates; their formations are not separated, but rather highly interacted. The APT results indicate that Mo partitions to the Ni3Ti precipitate core in the early stage of precipitation, which doubles the number density of Ni3Ti precipitates. Our calculations indicate that the Mo partitioning not only increases the chemical driving force, but also reduces the strain energy for nucleation, thereby accelerating Ni3Ti precipitation. As the precipitation proceeds, Mo atoms are rejected from the Ni3Ti precipitate core to the interface between the Ni3Ti precipitates and matrix, which leads to the heterogeneous nucleation of Mo-enriched precipitates on the outer surface of the Ni3Ti precipitates. This results in a substantial size refinement of Mo-enriched precipitates. In addition, the formation of Ni3Ti precipitates consumes Ni from the matrix, which substantially inhibits the spinodal decomposition and refines the size of Cr-rich precipitates. The cooperative strengthening of Ni3Ti, Mo-enriched, and Cr-rich co-precipitates leads to the development of new steels with a strength of 1.8 GPa; the contributions of these precipitates to the strengthening were quantitatively evaluated in terms of precipitate shearing and Orowan dislocation looping mechanisms.
KW - maraging steel
KW - mechanical property
KW - microstructure evolution
KW - precipitation
UR - http://www.scopus.com/inward/record.url?scp=85102252548&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2021.116788
DO - 10.1016/j.actamat.2021.116788
M3 - Journal article
AN - SCOPUS:85102252548
SN - 1359-6454
VL - 209
JO - Acta Materialia
JF - Acta Materialia
M1 - 116788
ER -