Insights into the microstructural design of high-performance Ti alloys for laser powder bed fusion by tailoring columnar prior-βgrains andα-Ti morphology  

作　　者：S.X.Wang S.F.Li X.M.Gan R.D.K.Misra R.Zheng K.Kondoh Y.F.Yang 

机构地区：[1]State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Key Laboratory of Science and Technology on Particle Materials,Chinese Academy of Sciences,Beijing 100190,China [4]Department of Metallurgical,Materials and Biomedical Engineering,University of Texas,El Paso TX 79968,USA [5]Joining and Welding Research Institution,Osaka University,11-1 Mihogaoka,Ibaraki,Osaka 567-0047,Japan

出　　处：《Journal of Materials Science & Technology》2024年第20期156-168,共13页材料科学技术（英文版）

基　　金：This work was supported by the National Natural Science Foun-dation of China(Nos.52074254,51874271,and 52174349);the Key Projects of International Cooperation(No.122111KYSB20200034);the Project of Key Laboratory of Science and Technology on Par-ticle Materials(No.CXJJ-22S043);the CAS Project for Young Scientists in Basic Research(No.YSBR-025);This work was finan-cially supported by the Selection of Best Candidates to Undertake Key Research Projects(No.211110230200);This research work was also financially supported by the OU Master Plan Implementation Project promoted under Osaka University.

摘　　要：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-βgrains and modifyingα-laths to equiaxed grains.Both Ni and B contributed to the refinement of columnar prior-βgrains during the L→βphase 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 ofα-Ti grains during theβ→αphase transformation.Together with the restricted growth ofα-laths induced by the refinement of prior-βgrains,a fully equiaxedα-Ti structure was obtained.The competition between the negative effect of brittle eutectoid and the positive role ofα-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 ofα-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.

关 键 词：Laser powder bed fusion Titanium alloys Grain refinement Powder processing Anisotropy 

分 类 号：TG146.23[一般工业技术—材料科学与工程]