Gradient nanostructure and residual stresses induced by Ultrasonic Nano-crystal Surface Modification in 304 austenitic stainless steel for high strength and high ductility
Chang Ye,Abhishek Telang,Amrinder S. Gill,Sergey Suslov,Yaakov Idell,Kai Zweiacker,Jörg M.K. Wiezorek,Zhong Zhou,Dong Qian,Seetha R. Mannava,Vijay K. Vasudevan +10 more
TLDR
In this paper, the effects of ultrasonic nano-crystal surface modification (UNSM) on residual stresses, microstructure changes and mechanical properties of austenitic stainless steel 304 were investigated.Abstract:
In this study, the effects of Ultrasonic Nano-crystal Surface Modification (UNSM) on residual stresses, microstructure changes and mechanical properties of austenitic stainless steel 304 were investigated. The dynamic impacts induced by UNSM leads to surface nanocrystallization, martensite formation, and the generation of high magnitude of surface compressive residual stresses (−1400 MPa) and hardening. Highly dense deformation twins were generated in material subsurface to a depth of 100 µm. These deformation twins significantly improve material work-hardening capacity by acting both as dislocation blockers and dislocation emission sources. Furthermore, the gradually changing martensite volume fraction ensures strong interfacial strength between the ductile interior and the two nanocrystalline surface layers and thus prevents early necking. The microstructure with two strong surface layers and a compliant interior embedded with dense nanoscale deformation twins and dislocations leads to both high strength and high ductility. The work-hardened surface layers (3.5 times the original hardness) and high magnitude of compressive residual stresses lead to significant improvement in fatigue performance; the fatigue endurance limit was increased by 100 MPa. The results have demonstrated that UNSM is a powerful surface engineering technique that can improve component mechanical properties and performance.read more
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Heterostructured materials: superior properties from hetero-zone interaction
Yuntian Zhu,Kei Ameyama,Peter M. Anderson,Irene J. Beyerlein,Huajian Gao,Hyoung Seop Kim,Enrique J. Lavernia,Suveen N. Mathaudhu,Haël Mughrabi,Robert O. Ritchie,Nobuhiro Tsuji,Xiangyi Zhang,Xiaolei Wu +12 more
Abstract: Heterostructured materials are an emerging class of materials with superior performances that are unattainable by their conventional homogeneous counterparts. They consist of heterogeneous zones wi...
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Improving surface finish and wear resistance of additive manufactured nickel-titanium by ultrasonic nano-crystal surface modification
Chi Ma,Mohsen Taheri Andani,Mohsen Taheri Andani,Haifeng Qin,Narges Shayesteh Moghaddam,Hamdy Ibrahim,Ahmadreza Jahadakbar,Amirehesam Amerinatanzi,Zhencheng Ren,Hao Zhang,Gary L. Doll,Yalin Dong,Mohammad Elahinia,Chang Ye +13 more
TL;DR: In this paper, an innovative surface processing technique, ultrasonic nano-crystal surface modification (UNSM), was used to mitigate the potential for the Ni ions release, which significantly improved surface finish and decrease surface porosity.
Journal ArticleDOI
Surface nanocrystallization of 17-4 precipitation-hardening stainless steel subjected to ultrasonic surface rolling process
TL;DR: In this article, an ultrasonic surface rolling process was used to treat 17-4 martensite precipitation-hardening (PH) stainless steels with a body-centered tetragonal (BCT) structure, and the deformation nanocrystallization mechanism was systematically investigated using microscopy and X-ray diffraction analysis.
Journal ArticleDOI
Laser shock peening without coating induced residual stress distribution, wettability characteristics and enhanced pitting corrosion resistance of austenitic stainless steel
TL;DR: Low energy laser shock peening without coating (LSPwC) was conducted on AISI 304 austenitic stainless steel specimens with varying pulse densities or overlapping as discussed by the authors, and the highest magnitude of compressive residual stress (CRS) was achieved for an optimized pulse density of 2500 pulses/cm 2 (75% overlapping).
Journal ArticleDOI
The effects of ultrasonic nanocrystal surface modification on the fatigue performance of 3D-printed Ti64
Hao Zhang,Richard Chiang,Haifeng Qin,Zhencheng Ren,Xiaoning Hou,Dong Lin,Gary L. Doll,Vijay K. Vasudevan,Yalin Dong,Chang Ye +9 more
TL;DR: In this article, an ultrasonic nanocrystal surface modification (UNSM) method was introduced for the processing of a 3D-printed Ti-6Al-4V alloy, which resulted in much better surface finish, lower subsurface porosity, and a high magnitude of compressive residual stresses, leading to significant improvement in rotation bending fatigue performance.
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