This study investigates the effects of ultrasonic nanocrystal surface modification (UNSM) on the microstructural evolution and tribological performance of a three-dimensional interconnected heterostructured compositionally complex alloy fabricated by liquid metal dealloying (LMD). The as-LMD microstructure comprises an interconnected Cu-rich phase and a CoCrFe-rich ligament phase. Electron backscatter diffraction reveals pronounced severe plastic deformation near the surface after UNSM, characterized by subgrain formation and increased intragranular misorientation. The kernel average misorientation distribution reveals a pronounced depth-dependent deformation gradient, with dislocations preferentially accumulating at the interphase boundaries. Vickers hardness increases from approximately 100–120 HV in the as-LMD condition to greater than 270 HV at the surface after UNSM, and the hardening effect remains detectable to a depth of approximately 500 μm. Compressive residual stresses are concentrated within the surface-adjacent ~50 μm. The solid ligament phase exhibits higher compressive residual stress than the Cu-rich phase, reflecting phase-dependent deformation accommodation and stress partitioning. Reciprocating wear tests show a narrower wear track, a markedly reduced wear depth, and a lower and more stable friction coefficient after UNSM. Microscopy shows oxide-layer cracking and delamination in the as-LMD condition, whereas the UNSM-treated surface exhibits minor abrasive wear of the tribo-film without delamination.

서 론
재료 및 방법
    시제품 제작
    현장 적용 실험
    기본 물성 분석
    표면 및 물성 변화 분석
    내후성 분석
결과 및 고찰
    기본 물성 분석
    표면 및 물성 변화 분석
    내후성 분석
결 론
사 사
References

• Yeji Kim(Department of Materials Science and Engineering, Dankook University, Cheonan 31116, Republic of Korea)
• Jae Hyuk Lee(Department of Materials Science and Engineering, Dankook University, Cheonan 31116, Republic of Korea)
• Soo-Hyun Joo(Department of Materials Science and Engineering, Dankook University, Cheonan 31116, Republic of Korea) Corresponding author
• Munsu Choi(Department of Materials Science and Engineering, Dankook University, Cheonan 31116, Republic of Korea, Extreme Materials Research Institute, Korea Institute of Materials Science, Changwon 51508, Republic of Korea)
• Jumi Choi(Department of Materials Science and Engineering, Dankook University, Cheonan 31116, Republic of Korea, Graduate Institute of Ferrous & Eco Materials Technology, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea)
• Hyoung Seop Kim(Graduate Institute of Ferrous & Eco Materials Technology, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea, Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea, Center for Heterogenic Metal Additive Manufacturing, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea ,Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan)
• Dong Jun Lee(Commercialization Research Division, Korea Institute of Materials Science (KIMS), Changwon 51508, Republic of Korea)
• Auezhan Amanov(Faculty of Engineering and Natural Sciences, Tampere University, PO Box 589, Tampere, FIN-33014, Finland)