Effect of Ti/Nb/Ta addition on the γ/γ'coherent microstructure in low-density and high-strength Co-Al-W-Mo-based superalloys

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外文摘要：Coherent precipitation of cuboidal γ'-Co3(Al,W)nanoparticles in face-centered-cubic(FCC)-γ matrix is of great significance for improving high-temperature mechanical properties of Co-based superalloys.The present work developed a series of low-density Co-based superalloys in light of the cluster composi-tion formula of[Al1-(Co,Ni)12]((Al0.5(Ti/Nb/Ta)0.5W0.5)(Mo0.5Cr0.5Co0.5)),where the addition of Ti,Nb,and Ta is mixed with an equimolar ratio.It is found that these designed alloys with different combinations of Ti/Nb/Ta,Ti/Nb,and Ti/Ta possess the coherent microstructure of cuboidal γ'nanoprecipitates in the FCC-y matrix.The microstructural evolution of coherent γ/γ'during aging at 1173 K shows that these superalloys exhibit higher thermal stability at high temperatures.Even after aging for 1000 h,there do not exist any other precipitated phases on grain boundaries,except the coarse γ'precipitates.Also,the coarsening rate constants of cuboidal γ'nanoprecipitates in these alloys are very low(K=5.76-6.03 nm3/s),which is mainly ascribed to a moderate lattice misfit(ε=0.28％-0.45％)between γ and γ'.The stable γ/γ'microstructure renders the alloys with prominent mechanical properties,as evidenced by the high yield strength of σYS=438-445 MPa at 1143 K.A large amount of stacking faults appear after compressive deformation and Lomer-Contrell dislocation locks are also formed due to the reaction of partial dislocations of stacking faults.Moreover,the microhardness(285-320 HV)in each alloy keeps almost constant with the aging time.Besides,these superalloys have a relatively lower density(8.67-8.89 g/cm3),among which the alloy containing Ti0.25Ta0.25 also exhibits a much higher γ'solvus temper-ature(1361±2 K)than those of the existing Co-Al-W-based superalloys.

外文关键词：

Co-based superalloysCoherent microstructureLattice misfitParticle coarseningMechanical properties

作者：

Jinlin Li、Jiaqi Zhang、Zhen Li、Qing Wang、Chuang Dong、Fen Xu、Lixian Sun、Peter K.Liaw

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作者单位：

School of Materials Science and Engineering,Engineering Research Center of High Entropy Alloy Materials(Liaoning Province),Dalian University of Technology,Dalian 116024,China

School of Aeronautics and Astronautics,Shenyang Aerospace University,Shenyang 110136,China

School of Mechanical Engineering,Dalian University of Technology,Dalian 116024,China

Guangxi Collaborative Innovation Center of Structure and Property for New Energy Materials,Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology,Guilin 541004,China

Department of Materials Science and Engineering,The University of Tennessee,Knoxville,37996,TN,USA

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基金：

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaKey Discipline and Major Project of Dalian Science and Technology Innovation FoundationGuangxi Key Laboratory of Information Laboratory FoundationNational Science FoundationNational Science FoundationNational Science Foundation

项目编号：

5217115291860108U18672012020JJ25CY004221013-KDMR-161118018096402226508

出版年：

2024

DOI：

10.1016/j.jmst.2023.11.021

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)

参考文献量67