Fatigue behaviour of a laser beam welded CoCrFeNiMn-type high entropy alloy

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:766

Article

Kashaev, Nikolai¹  Ventzke, Volker¹  Petrov, Nikita¹  Horstmann, Manfred¹  Zherebtsov, Sergey²  Shaysultanov, Dmitry²  Sanin, Vladimir³  Stepanov, Nikita² 

[1] Helmholtz Zentrum Geesthacht, Dept Laser Proc & Struct Assessment, Inst Mat Res, Mat Mech, Max Planck Str 1, D-21502 Geesthacht, Germany

[2] Belgorod State Univ, Pobeda 85, Belgorod 308015, Russia

[3] Russian Acad Sci, Inst Struct Macrokinet & Mat Sci, Academician Osipyan Str 8, Chernogolovka 142432, Moscow Region, Russia

关键词: High entropy alloy;    Laser beam welding;    Microstructure;    Tensile strength;    Fatigue;   

DOI  :  10.1016/j.msea.2019.138358

来源: Elsevier

【 摘 要 】

Laser beam welding was used to produce butt joints from the CoCrFeNiMn-type high entropy alloy. The alloy in the initial condition had an fcc single-phase coarse-grained structure. Laser welding resulted in the M7C3-type carbides precipitation in the fcc matrix. The carbide particles precipitation resulted in a considerable increase in microhardness from 150 HV 0.5 for the as-sintered condition to 205 HV 0.5 in the fusion zone. Laser beam welding had a negligible effect on both static mechanical properties and fatigue behaviour of the alloy. The endurance limit of either type of specimens (i.e. with and without welding seam) was 200 MPa. Fracture of all specimens with the laser beam welded seams occurred in the base material area during both tensile and fatigue testing. Weak effect of welding on static/fatigue behaviour of the alloy can be attributed to the higher hardness of the fusion zone, resulting in strain localization in the base material area. An increase in load resulted in activation of secondary slip systems and formation of deformation twins in fatigue specimens.

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