TY - JOUR

T1 - Quasi-in-situ observation of microstructure at the friction interface

T2 - Shear deformation, dynamic recrystallization and mechanical responses during friction welding process

AU - Jin, Feng

AU - Fu, Banglong

AU - Shen, Junjun

AU - Li, Jinglong

AU - Li, Wenya

AU - Santos, Jorge F. dos

AU - Klusemann, Benjamin

N1 - Declaration of Competing Interest None. Acknowledgements This work was supported by the research fund of the National Natural Science Foundations of China (Grant No. 52205416) and the China Postdoctoral Science Foundation (2021M692627). Feng Jin is grateful for financial support from the Chinese Scholarship Council (CSC 202106290001). The authors declare they have no conflict of interest. Publisher Copyright: © 2023 Elsevier Inc.

PY - 2023/6/1

Y1 - 2023/6/1

N2 - Friction based joining processes are monitored and controlled according to the collectable and measurable mechanical responses, such as torque or temperature, during the process. These are a result of the underlying physical microstructural mechanism during the process, where joints are formed under shear deformation (SD) and/or dynamic recrystallization (DRX). To ensure a first quality assessment of the joints during processing, it is critical to precisely investigate the relation between (macro)-mechanical and microstructural responses (SD and DRX). In the present study, the transition from SD to DRX in friction welding has been focused and quasi in-situ observed by ‘stop - action’ rotary friction welding (RFW) experiments coupled with electron back-scattered diffraction (EBSD) analysis using pipe structures, which clarifies the characteristics of the mechanical response. Further RFW experiments with different parameters were conducted to obtain a suitable relation that correlate the DRX transition temperatures to the welding parameters. Thereafter, further ‘stop - action’ RFW experiments were performed on rod structures to investigate the spatial - temporal distribution of SD - DRX at the friction interface and accordingly the friction torque characteristics. The results show that the transition from SD to DRX takes place at the peak torque (PT) and the temperature inflection point (TIP). The TIP of pipe-structure specimens is the critical DRX temperature during FW, which is dominated by friction linear speed. The PT is the threshold that distinguishes the dominating mechanism, SD or DRX, at the welding interface when welding rod structures.

AB - Friction based joining processes are monitored and controlled according to the collectable and measurable mechanical responses, such as torque or temperature, during the process. These are a result of the underlying physical microstructural mechanism during the process, where joints are formed under shear deformation (SD) and/or dynamic recrystallization (DRX). To ensure a first quality assessment of the joints during processing, it is critical to precisely investigate the relation between (macro)-mechanical and microstructural responses (SD and DRX). In the present study, the transition from SD to DRX in friction welding has been focused and quasi in-situ observed by ‘stop - action’ rotary friction welding (RFW) experiments coupled with electron back-scattered diffraction (EBSD) analysis using pipe structures, which clarifies the characteristics of the mechanical response. Further RFW experiments with different parameters were conducted to obtain a suitable relation that correlate the DRX transition temperatures to the welding parameters. Thereafter, further ‘stop - action’ RFW experiments were performed on rod structures to investigate the spatial - temporal distribution of SD - DRX at the friction interface and accordingly the friction torque characteristics. The results show that the transition from SD to DRX takes place at the peak torque (PT) and the temperature inflection point (TIP). The TIP of pipe-structure specimens is the critical DRX temperature during FW, which is dominated by friction linear speed. The PT is the threshold that distinguishes the dominating mechanism, SD or DRX, at the welding interface when welding rod structures.

KW - Friction welding

KW - Shear deformation

KW - Dynamic recrystallization

KW - Mechanical responses

KW - Stop-action

KW - Electron back-scattered diffraction

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85152147760&partnerID=8YFLogxK

U2 - 10.1016/j.matchar.2023.112911

DO - 10.1016/j.matchar.2023.112911

M3 - Journal articles

VL - 200

JO - Materials Characterization

JF - Materials Characterization

SN - 1044-5803

M1 - 112911

ER -