Near-equiaxed β grain was achieved in the near-α Ti60(Ti-5.7Al-4.0Sn-3.5Zr-0.4Mo-0.4Si-0.4Nb-1.0Ta-0.05C)titanium alloy via laser directed energy deposition(LDED).The microstructural evolution along the building direction and the room-temperature tensile properties along the horizontal and vertical direc-tions(building direction)were systematically studied through SEM and OM.EBSD and XRD were utilized to accurately demonstrate the texture of the α and β phases.The results showed that the α phase pre-sented a low texture intensity,which was ascribed to the weak textured β grain with near-equiaxed mor-phology,since there are Burgers orientation relationships during the β→α transition.In addition,numer-ical simulation,combined with the CET curve of Ti60 alloy considering the effect of multi-composition,was utilized to elucidate the formation mechanism of the near-equiaxed β grains.Furthermore,according to the solidification theory,we proposed that the solidification temperature range ATf was more accurate than the growth restriction factor Q in predicting the formation tendency of equiaxed β grain in differ-ent titanium alloys.Tensile results showed that the horizontal and vertical samples had similar strength,while the former exhibited larger elongation than the latter.The effect of the near-equiaxed β grain and the internal α phase on mechanical properties were revealed at last.

MengCheng Deng;Shang Sui;Bo Yao;Liang Ma;Xin Lin;Jing Chen

State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China;Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design,MIIT China,Northwestern Polytechnical University,Xi'an 710072,China

材料科学技术（英文版）

[1]MengCheng Deng;Shang Sui;Bo Yao;Liang Ma;Xin Lin;Jing Chen-.Microstructure and room-temperature tensile property of Ti-5.7Al-4.0Sn-3.5Zr-0.4Mo-0.4Si-0.4Nb-1.0Ta-0.05C with near equiaxed β grain fabricated by laser directed energy deposition technique)[J].材料科学技术（英文版）,2022(06):308-320

0Ta,ATf

Microstructure,room,temperature,tensile,property,7Al,0Sn,5Zr,4Mo,4Si,4Nb,05C,near,equiaxed,fabricated,by,laser,directed,energy,deposition,technique,Near,was,achieved,Ti60,titanium,via,LDED,microstructural,evolution,along,building,direction,properties,horizontal,vertical,were,systematically,studied,through,OM,EBSD,utilized,accurately,demonstrate,phases,results,showed,that,sented,low,intensity,which,ascribed,weak,textured,phology,since,there,are,Burgers,orientation,relationships,during,transition,In,addition,numer,simulation,combined,CET,curve,considering,effect,multi,composition,elucidate,formation,mechanism,grains,Furthermore,according,solidification,theory,proposed,range,than,growth,restriction,predicting,tendency,differ,alloys,Tensile,samples,had,similar,strength,while,former,exhibited,larger,elongation,latter,internal,mechanical,revealed,last

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