Tensile properties of a nanocrystalline 316L austenitic stainless steel
TL;DR: In this article, a nanocrystalline 316L austenitic stainless steel sample (mean grain size similar to 40 nm) was prepared by means of surface mechanical attrition treatment, which exhibited an extremely high yield strength up to 1450 MPa, which still follows the Hall-Petch relation extrapolated from the coarse-grained material.
About: This article is published in Scripta Materialia.The article was published on 2005-05-01. It has received 392 citations till now. The article focuses on the topics: Austenitic stainless steel & Nanocrystalline material.
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Abstract: This article presents an overview of the developments in stainless steels made since the 1990s. Some of the new applications that involve the use of stainless steel are also introduced. A brief introduction to the various classes of stainless steels, their precipitate phases and the status quo of their production around the globe is given first. The advances in a variety of subject areas that have been made recently will then be presented. These recent advances include (1) new findings on the various precipitate phases (the new J phase, new orientation relationships, new phase diagram for the Fe–Cr system, etc.); (2) new suggestions for the prevention/mitigation of the different problems and new methods for their detection/measurement and (3) new techniques for surface/bulk property enhancement (such as laser shot peening, grain boundary engineering and grain refinement). Recent developments in topics like phase prediction, stacking fault energy, superplasticity, metadynamic recrystallisation and the calculation of mechanical properties are introduced, too. In the end of this article, several new applications that involve the use of stainless steels are presented. Some of these are the use of austenitic stainless steels for signature authentication (magnetic recording), the utilisation of the cryogenic magnetic transition of the sigma phase for hot spot detection (the Sigmaplugs), the new Pt-enhanced radiopaque stainless steel (PERSS) coronary stents and stainless steel stents that may be used for magnetic drug targeting. Besides recent developments in conventional stainless steels, those in the high-nitrogen, low-Ni (or Ni-free) varieties are also introduced. These recent developments include new methods for attaining very high nitrogen contents, new guidelines for alloy design, the merits/demerits associated with high nitrogen contents, etc.
1,668 citations
TL;DR: The potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications is demonstrated, with austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibiting a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels.
Abstract: Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.
1,385 citations
TL;DR: In this article, the authors show that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal modulator that is able to slow down but not entirely block the dislocation motion.
557 citations
TL;DR: In this paper, a feasibility study was performed to fabricate ITER In-Vessel components by Selective Laser Melting (SLM) supported by Fusion for Energy (F4E), almost fully dense 316L stainless steel (SS316L) components were prepared from gas-atomized powder and with optimized SLM processing parameters.
509 citations
TL;DR: In this paper, the effect of a nanocrystalline surface layer on the fatigue behavior of a 316L stainless steel is investigated, and significant enhancements of the yield stress and the fatigue limit have been achieved through surface mechanical attrition treatment (SMAT).
435 citations
References
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01 Jul 2004-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a surface mechanical attrition treatment (SMAT) was developed for synthesizing a nanostructured surface layer on metallic materials in order to upgrade the overall properties and performance.
Abstract: In terms of the grain refinement mechanism induced by plastic straining, a novel surface mechanical attrition treatment (SMAT) was developed for synthesizing a nanostructured surface layer on metallic materials in order to upgrade the overall properties and performance. In this paper, the SMAT technique and the microstructure of the SMAT surface layer will be described. The grain refinement mechanism of the surface layer during the SMAT will be analyzed in terms of the microstructure observations in several typical materials. Obvious enhancements in mechanical properties and tribological properties of the nanostructured surface layer in different materials were observed. Further development and prospects will be addressed with respect to the SMAT as well as the performance and technological applications of the engineering materials with the nanostructured surface layer.
910 citations
TL;DR: A grain refinement mechanism induced by plastic deformation during the SMA treatment in Fe was proposed in this article, which involves formation of dense dislocation walls (DDWs) and dislocation tangles (DTs) in original grains and in the refined cells under further straining.
889 citations
TL;DR: The microstructure in the surface layer of a pure iron plate was refined at the nanometer scale by means of a surface mechanical attrition treatment that generates repetitive severe plastic deformation of the surfaceLayer to provide a new approach for selective surface reactions in solids.
Abstract: The microstructure in the surface layer of a pure iron plate was refined at the nanometer scale by means of a surface mechanical attrition treatment that generates repetitive severe plastic deformation of the surface layer. The subsequent nitriding kinetics of the treated iron with the nanostructured surface layer were greatly enhanced, so that the nitriding temperature could be as low as 300°C, which is much lower than conventional nitriding temperatures (above 500°C). This enhanced processing method demonstrates the technological significance of nanomaterials in improving traditional processing techniques and provides a new approach for selective surface reactions in solids.
581 citations
Book•
01 Jan 2003
TL;DR: This book discusses the fundamental theories and mechanisms of failure, and practical failure assessment methods, used in structural integrity assessment and bioengineering.
Abstract: Volume 1: Structural integrity assessment - examples and case studies, (I. Milne et al). Volume 2: Fundamental theories and mechanisms of failure, (B. Karihaloo, W.G. Knauss). Volume 3: Numerical and computational methods, (R. de Borst, H.A Mang). Volume 4: Cyclic loading and fatigue, (R.O. Ritchie, Y. Murakami). Volume 5: Creep and high-temperature failure, (A. Saxena, H.K.D.H. Bhadeshia). Volume 6: Environmentally-assisted fracture, (J. Petit, P. Scott). Volume 7: Practical failure assessment methods, (R.A. Ainsworth, K-H Schwalbe). Volume 8: Interfacial and nanoscale failure, (W. Gerberich, W. Yang). Volume 9: Bioengineering, (Y-W Mai, S-H Teoh). Volume 10: Index volume.
407 citations
"Tensile properties of a nanocrystal..." refers background in this paper
...Although the residual compressive stresses could be induced by SMAT processing in the nc samples, the macroscopic residual stresses were relaxed after the thin layer of nanostructure was taken off because the gradient of the macrostress is quite small between the top and the bottom of thin specimens [13]....
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30 Jun 2000-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a new technique was introduced to realize surface nanocrystallization (i.e., generation of a surface layer of nanostructures) on a 316L stainless steel by means of ultrasonic shot peening treatment.
Abstract: A new technique was introduced to realize surface nanocrystallization (i.e. generation of a surface layer of nanostructures) on a 316L stainless steel by means of ultrasonic shot peening treatment. The microstructural evolution of the 316L stainless steel was characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. After the ultrasonic shot peening treatment, obvious grain refinement was observed and a nanocrystalline surface layer was found. The thickness of the nanocrystalline surface layer varies from a few to about 30 μm depending upon the treatment duration and the grain size increases from about 10 nm at the top surface layer, gradually to more than 100 nm at a depth of ≈30 μm. The nanocrystallization mechanism was analyzed in terms of the deformation behavior and TEM observations of the microstructural evolution of the treated samples.
404 citations