A critical evaluation of microstructure-texture-mechanical behavior heterogeneity in high pressure torsion processed CoCuFeMnNi high entropy alloy

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

卷:782

Article

Sonkusare, Reshma¹  Biswas, Krishanu¹  Al-Hamdany, Nowfal²  Brokmeier, H. G.²  Kalsar, R.³  Schell, Norbert⁴  Gurao, N. P.¹ 

[1] Indian Inst Technol Kanpur, Dept Mat Sci & Engn, Kanpur 208016, Uttar Pradesh, India

[2] Clausthal Univ Technol IWW TEXMAT, Agricolastr 6, D-38678 Clausthal Zellerfeld, Germany

[3] Indian Inst Sci, Dept Mat Engn, Bangalore 560012, Karnataka, India

[4] DESY, Helmholtz Zentrum Geesthacht, German Engn Mat Sci Ctr, Hamburg, Germany

关键词: High entropy alloy;    High pressure torsion;    Shear texture;    Synchrotron diffraction;    Heterogeneity;    Strengthening mechanisms;   

DOI  :  10.1016/j.msea.2020.139187

来源: Elsevier

【 摘 要 】

The present study aims to understand the evolution of textural and microstructural heterogeneity and its effect on evolution of mechanical properties of an equiatomic FCC CoCuFeMnNi high entropy alloy (HEA) disc subjected to high pressure torsion (HPT). HPT was performed on disc specimen with a hydrostatic pressure of 5 GPa for 0.1, 0.5, 1 and 5 turns at room temperature where the hardness saturated at 1941 MPa at the periphery of the sample after five turns. Synchrotron diffraction texture analysis of five-turn HPT sample reveals characteristic shear texture with the dominance of A {1(sic)(sic)}< 110 > and A* {1(sic)(sic)}< 112 > components near central region of the disc and it shifts to C {001}< 110 > component near the periphery of the disc. X-ray diffraction analysis shows decrease in crystalline size with simultaneous increase in dislocation density for five-turn HPT sample with increasing strain from centre to the periphery of the disc. Microstructural analysis using electron back scatter diffraction and transmission electron microscopy indicates extensive grain fragmentation (approximate to 55 nm) at the periphery of five-turn sample. The evolution of hardness from centre to the periphery of the disc cannot be explained only on the basis of evolution of grain size and dislocation density. The increase in contribution from solid solution strengthening due to partial dissolution of copper rich nano-clusters is expected to be the underlying cause for increase in the hardness. Thus, evolution of gradient microstructure, texture, and chemistry opens up new vistas for designing functionally graded materials for engineering applications.

【 授权许可】

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