GyeongSeok Joo

Korea Automotive Technology Institute

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SeHoon Kim

Korea Automotive Technology Institute

MinSang Kim

Korea Automotive Technology Institute

Yongwook Song

Kookmin University

Soon‐Mok Choi

Korea University of Technology and Education

JaeHyuk Shin

Korea Automotive Technology Institute

Hyunjoo Choi

Kangwon National University

YoungKil Jung

Korea Automotive Technology Institute

Jae-hyuck Shin

Korea Automotive Technology Institute

Suwon Park

Materials Science & Engineering

SeungGyu Choi

Korea Automotive Technology Institute

Cooperative Institutions

Korea Automotive Technology Institute

Kookmin University

Materials Science & Engineering

Kangwon National University

Yonsei University

Korea Advanced Institute of Science and Technology

University of Kentucky

Nanjing Agricultural University

University of Notre Dame

Harbin Electric Corporation (China)

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Effect of Minor Elements Content on the Phase Formation and Mechanical Properties of 6xxx Series Aluminum Alloy Sheets

Journal of Materials Engineering and Performance (2023)

GyeongSeok Joo Yongwook Song MinSang Kim JaeHyuk Shin Soon‐Mok Choi

Ductility (Earth science)

Stacking-fault energy

Hardening (computing)

10.1007/s11665-023-08211-x

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Research on Alloy Design and Process Optimization of Al–Mg–Zn-Cu-Based Aluminum Alloy Sheets for Automobiles with Secured Formability and Bake-Hardenability

Metals (2024)

GyeongSeok Joo SeungGyu Choi YoungKil Jung SeHoon Kim Jae-hyuck Shin

In this study, the compositional design of high-formability, high-bake-hardening Al–Mg–Zn-Cu-based aluminum alloys was carried out, and process conditions were established to secure mechanical properties under harsh conditions for Al–Mg–Zn-Cu-based alloys. Using JMatPro13.0 for precipitation phase simulation, the optimal pre-aging temperature and time of the design composition were selected. Through the introduction of pre-aging, it was confirmed that no over-aging phenomena occurred, even after bake-hardening, and it was confirmed that it could have mechanical properties similar to those of test specimens subjected to traditional heat treatment. Through DSC (Differential Scanning Calorimetry) and TEM (Transmission Electron Microscope) analyses, it was found that pre-aging provided sufficient thermal stability to the GP (Guinier–Preston) zone and facilitated transformation to the η’-phase. In addition, it was confirmed that, even under bake-hardening conditions, coarsening of the precipitation phase was prevented and number density was increased, thereby contributing to improvements in the mechanical properties. The designed alloy plate was evaluated as having excellent anisotropy properties through n-value and r¯-value calculations, and it was confirmed that a similar level of formability was secured through FLC (Forming Limit Curve) comparison with commercial plates.

Hardenability

10.3390/met14060618

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Effect of Mg Content on Precipitation Hardening Behavior of Al–Mg–Si–(Cu) Alloys

MATERIALS TRANSACTIONS (2023)

GyeongSeok Joo Yongwook Song MinSang Kim Suwon Park JaeHyuk Shin

This study investigates the effect of Mg content on precipitation behavior and resulting mechanical properties of Al–Mg–Si(–Cu) alloy plates manufactured by gravity casting and cold rolling. An alloy with a relatively low Mg content (0.3 wt%) remains after baking hardening without sufficient transformation of Mg–Si clusters or stable Mg2Si in the low temperature phase, whereas, alloys with relatively high Mg content mainly form major strengthening contributors such as β′- and β′′ phases. DSC analysis combined by thermodynamic modeling demonstrates that the formation of β′- or β′′-phases in the 0.3 Mg samples requires much high pre-aging (P.A.) temperatures, which limits improvement of strength by bake hardening (B.H.). This new observation provides the guideline to design the content of Mg and pre-aging condition to obtain optimal bake-hardening characteristics for Al–Mg–Si(–Cu) alloys.

Precipitation hardening

Hardening (computing)

Solid solution strengthening

10.2320/matertrans.mt-mi2022003

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Citations (1)