首页|Thermal stabilizing and toughening of a dual-phase Nb alloy by tuning stabilizing element C in Nb-BCC

Thermal stabilizing and toughening of a dual-phase Nb alloy by tuning stabilizing element C in Nb-BCC

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Niobium alloys have found extensive application in industries,such as aerospace,nuclear reactor,and emerging electronic technologies,owing to their high melting point,low density,and remarkable forma-bility.Nevertheless,they still fall short in terms of comprehensive strength,toughness,and thermal stability when subjected to complex impacts and/or torsional forces during service.Here,a dual-phase(BCC/FCC)Nb alloy with attractive mechanical properties and thermal stability was designed by tuning stable element C in the Nb-BCC matrix assisted by hot deformation and aging processes.Our findings reveal that the formation of discontinuous carbides at the grain boundary promotes the phase trans-formation of the matrix from BCC to FCC(K-S orientation relationship),resulting in the formation of FCC thin layers and nano particles.This unique configuration hinders the slipping of dislocations during deformation and impedes the degeneration of microstructures during the thermal cycling process from 200 ℃ to 900 ℃.Moreover,the discontinuous carbides at GBs provide channels to transfer dislocations between various phases and/or grains,which results in attractive mechanical properties and thermal sta-bility.The ultimate tensile strength,yield strength,elongation,and elasticity modulus of the designed Nb alloy reach impressive values of 790.5 MPa,436.5 MPa,39.1%,and 63.5 MPa,respectively.These obser-vations provide guidelines for designing dual-phase Nb alloys with remarkable strength,toughness,and thermal stability for aerospace applications by tuning the stabilizing element C in the Nb-BCC matrix.

StrengthToughnessThermal stabilityCarbideDual-phaseNb superalloys

Yafang Zhang、Xiaojun Zhao、Sainan Liu、Wei Li、Kechao Zhou、Lairong Xiao、Miao Song、Zhenyang Cai

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School of Materials Science and Engineering,Central South University,Changsha 410083,China

Key Laboratory of Non-ferrous Metal Materials Science and Engineering,Ministry of Education,Central South University,Changsha 410083,China

Center for Mineral Materials,School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China

Powder Metallurgy Research Institute,Central South University,Changsha 410083,China

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National Natural Science Foundation of ChinaHunan Province Natural Science Foundation

519012522023JJ30684

2024

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子:0.657
ISSN:1005-0302
年,卷(期):2024.186(19)
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