In the present study,the micro-mechanical behavior of CoCrFeMnNi high-entropy alloy was investigated using an in-house micro-tensile setup at room temperature and 550℃at different strain rates.Micro-mechanical properties are compared with those obtained using a commercial macro-tensile setup to check a potential sample size effect.Results show that mechanical properties such as yield strength,ultimate tensile strength and uniform elongation are independent of the sample size.However,the to-tal elongation-to-failure of micro-samples is found to be lower than those of macro-counterparts.Apart from this,the material exhibits serrated plastic flow,which is strain rate dependent in terms of the onset strain and shape of serrations at 550℃.Furthermore,transmission electron microscopy investigations were performed to correlate the occurrence of serrations to the observed distinct dislocation structures.Microstructural results provide direct evidence that dislocations are curved and hence effectively pinned and unpinned at the lowest applied strain rate,which might be responsible for the occurrence of serrated plastic flow.

Kaiju Lu;Ankur Chauhan;Dimitri Litvinov;Aditya Srinivasan Tirunilai;Jens Freudenberger;Alexander Kauffmann;Martin Heilmaier;Jarir Aktaa

Institute for Applied Materials,Karlsruhe Institute of Technology(KIT),Hermann-von-Helmholtz-Platz 1,76344 Eggenstein Leopoldshafen,Germany;Institute for Applied Materials,Karlsruhe Institute of Technology(KIT),Engelbert-Arnold-Strasse 4,76131 Karlsruhe,Germany;Leibniz Institute for Solid State and Materials Research Dresden(IFW Dresden),Helmholtzstr,20,D-01069 Dresden,Germany;Institute of Materials Science,Technische Universit?t Bergakademie Freiberg,Gustav-Zeuner-Str,5,09599 Freiberg,Germany

材料科学技术（英文版）

[1]Kaiju Lu;Ankur Chauhan;Dimitri Litvinov;Aditya Srinivasan Tirunilai;Jens Freudenberger;Alexander Kauffmann;Martin Heilmaier;Jarir Aktaa-.Micro-mechanical deformation behavior of CoCrFeMnNi high-entropy alloy)[J].材料科学技术（英文版）,2022(05):237-245

serrations,unpinned

mechanical,deformation,behavior,CoCrFeMnNi,high,entropy,alloy,In,present,study,was,investigated,using,house,tensile,setup,room,temperature,different,strain,rates,properties,compared,those,obtained,commercial,macro,check,potential,size,Results,show,that,such,yield,strength,ultimate,uniform,elongation,independent,However,tal,failure,samples,found,lower,than,counterparts,Apart,from,this,material,exhibits,serrated,plastic,flow,which,terms,onset,shape,Furthermore,transmission,electron,microscopy,investigations,were,performed,correlate,occurrence,observed,distinct,structures,Microstructural,results,provide,direct,evidence,dislocations,curved,hence,effectively,lowest,applied,might,responsible

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