Bimodal grain microstructure development during hot compression of a cast-homogenized Mg-Zn-Zr alloy

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

卷:724

Article

Hadadzadeh, A.¹  Mokdad, F.²  Amirkhiz, B. Shalchi³  Wells, M. A.¹  Williams, B. W.³  Chen, D. L.² 

[1] Univ Waterloo, Mech & Mechatron Engn Dept, 200 Univ Ave West, Waterloo, ON N2L 3G1, Canada

[2] Ryerson Univ, Dept Mech & Ind Engn, 350 Victoria St, Toronto, ON M5B 2K3, Canada

[3] Nat Resources Canada, CanmetMAT, 183 Longwood Rd South, Hamilton, ON L8P 0A5, Canada

关键词: Magnesium alloy;    Dynamic recrystallization;    EBSD;    HRTEM;    Dislocation;   

DOI  :  10.1016/j.msea.2018.03.112

来源: Elsevier

【 摘 要 】

Hot deformation of a cast-homogenized ZK60 alloy was studied by compression at a temperature of 450 degrees C and a strain rate of 0.001 s(-1) to investigate microstructural evolution. The deformed microstructure was characterized using electron backscatter diffraction (EBSD) and high resolution transmission electron microscopy (HRTEM). EBSD observations of the deformed microstructure showed that hot deformation of this alloy resulted in a bimodal grain microstructure consisting of large pancaked unrecrystallized dendrites surrounded by recrystallized equiaxed fine grains. HRTEM studies revealed the presence of nano-(Zn-Zr)-precipitates in the deformed microstructure. Due to the coherency of precipitates/matrix, the dislocations were pinned by the nanoprecipitates inside the unrecrystallized grains and the dislocation motion inside the grains was impeded, hence, a substructure evolved. Consequently, dynamic recrystallization (DRX) was suppressed and deformation was concentrated inside the DRXed region.

【 授权许可】

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