Insights into the microstructural design of high-performance Ti alloys for laser powder bed fusion by tailoring columnar prior-β grains and α-Ti morphology

S.X.Wang ¹S.F.Li ¹X.M.Gan ¹R.D.K.Misra ²R.Zheng ¹K.Kondoh ³Y.F.Yang⁴

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作者信息

1. State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China
2. Department of Metallurgical,Materials and Biomedical Engineering,University of Texas,El Paso TX 79968,USA
3. Joining and Welding Research Institution,Osaka University,11-1 Mihogaoka,Ibaraki,Osaka 567-0047,Japan
4. State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Science and Technology on Particle Materials,Chinese Academy of Sciences,Beijing 100190,China;Joining and Welding Research Institution,Osaka University,11-1 Mihogaoka,Ibaraki,Osaka 567-0047,Japan
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Abstract

A high-performance Ti-Ni-B alloy with good tensile properties and reduced mechanical anisotropy was developed by promoting the columnar to equiaxed transition(CET)of prior-β grains and modifying α-laths to equiaxed grains.Both Ni and B contributed to the refinement of columnar prior-β grains during the L→β phase transformation by generating constitutional undercooling.Compared with Ni,B had a su-perior capability of generating constitutional undercooling,which not only replaced a significant amount of Ni with a minor addition to reduce the formation of brittle eutectoid,but also reacted with Ti to form TiB to promote heterogeneous nucleation of α-Ti grains during the β→α phase transformation.Together with the restricted growth of α-laths induced by the refinement of prior-β grains,a fully equiaxed α-Ti structure was obtained.The competition between the negative effect of brittle eutectoid and the positive role of α-lath to equiaxed grain transition on the ductility of as-printed Ti-Ni-B alloys was fundamen-tally governed by the morphology of eutectoid and technically dependent on the Ni-B content.When the addition was 1.2Ni-0.06B(wt.％)or less,the positive effect of α-lath on equiaxed grain transition can effectively mitigate the issue of reduced ductility caused by brittle eutectoid.In contrast,at 1.8Ni-0.09B or greater,the negative effect of eutectoid dominated.New insights into microstructural design obtained through the aforementioned approach were presented and discussed.

Key words

Laser powder bed fusion/Titanium alloys/Grain refinement/Powder processing/Anisotropy

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基金项目

National Natural Science Foundation of China(52074254)

National Natural Science Foundation of China(51874271)

National Natural Science Foundation of China(52174349)

Key Projects of International Cooperation(122111KYSB20200034)

Project of Key Laboratory of Science and Technology on Particle Materials(CXJJ-22S043)

CAS Project for Young Scientists in Basic Research(YSBR-025)

Selection of Best Candidates to Undertake Key Research Projects(211110230200)

OU Master Plan Implementation Project promoted under Osaka University()

出版年

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

参考文献量46

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