Multimodal analysis of spatially heterogeneous microstructural refinement and softening mechanisms in three-pass friction stir processed Al-4Si alloy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:887

Article

Escobar, Julian¹  Gwalani, Bharat¹  Olszta, Matthew²  Silverstein, Joshua²  Overman, Nicole²  Bergmann, Luciano³  dos Santos, Jorge F.^2,3  Staron, Peter⁴  Maawad, Emad⁴  Klusemann, Benjamin^3,5  Mathaudhu, Suveen^2,6,7  Devaraj, Arun¹ 

[1] Pacific Northwest Natl Lab, Phys & Computat Sci Directorate, Richland, WA 99354 USA

[2] Pacific Northwest Natl Lab, Energy & Environm Directorate, Richland, WA 99354 USA

[3] Helmholtz Zentrum Hereon, Inst Mat Mech, D-21502 Geesthacht, Germany

[4] Helmholtz Zentrum Hereon, Inst Mat Phys, D-21502 Geesthacht, Germany

[5] Leuphana Univ Luneburg, Inst Prod & Proc Innovat, D-21335 Luneburg, Germany

[6] Univ Calif Riverside, Mat Sci & Engn Program, Riverside, CA 92521 USA

[7] Univ Calif Riverside, Mech Engn Dept, Riverside, CA 92521 USA

关键词: Al-4Si;    Friction stir processing;    Geometric dynamic recrystallization;    Grain fragmentation;    Synchrotron X-ray diffraction;   

DOI  :  10.1016/j.jallcom.2021.161351

来源: Elsevier

【 摘 要 】

Solid phase processing methods such as friction stir processing (FSP) offer pathways to refine the microstructure of metallic alloys through the combined action of deformation and deformation-induced heating. However, this thermomechanical coupling during FSP also leads to the occurrence of multiple competing microstructural evolution mechanisms which in turn can lead to locally varying mechanical properties, often distributed heterogeneously in the microstructure. This inherent microstructural and mechanical property heterogeneity in alloys subjected to FSP makes it rather challenging to reveal the microstructure mechanical property relationships systematically. Therefore in this work, we systematically analyze the relationship between microstructural evolution and local microhardness in a model binary Al-4 at.% Si alloy subjected to three-pass friction stir processing. Spatially resolved high-energy synchrotron X-ray diffraction, electron backscattered diffraction, and scanning transmission electron microscopy were used to understand the heterogeneous microstructural evolution due to the FSP. Our results provide insight into how particle-stimulated grain nucleation, recovery, and recrystallization occur heterogeneously in the Al-Si alloy as a function of the distance from the stir zone, directly influencing the degree of softening. The systematic understanding developed by this work can guide future studies on the influence of FSP process parameters on the microstructural evolution mechanisms and its influence on local mechanical properties (c) 2021 Published by Elsevier B.V.

【 授权许可】

Free