Microstructure and Performance of Surface Nanostructure 316L Stainless Steel Induced by Wire-Brushing Deformation

2011 ◽  
Vol 682 ◽  
pp. 115-119 ◽  
Author(s):  
Ling Zhu ◽  
Xin Min Fan
Keyword(s):  
Stainless Steel ◽  
Surface Layer ◽  
Grain Refinement ◽  
High Speed ◽  
316L Stainless Steel ◽  
Xrd Analysis ◽  
Nanostructured Surface ◽  
Wire Brushing ◽  
Surface Nanostructure ◽  
And Performance

Nanostructured surface layer was synthesized on 316L stainless steel by means of high-speed rotation wire-brushing deformation (HRWD). The refined microstructure features were systematically characterized by optical microscopy (OM), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) observations. Furthermore, the microhardness was examined by microhardness tester. After HRWD treatment, obvious grain refinement was observed and a nanocrystalline surface layer was formed on 316L stainless steel. It was found that a gradient microstructure with grain size from nanoscale to microscale was obtained along the depth of its surface layer. The thickness of the nanocrystalline surface layer varies from a few to about 20μm depending upon the treatment duration and compressive stress. The microhardness of nanostructured surface layer was enhanced significantly, and along the depth from the top surface, the microhardness in the surface gradually decreased to that of the matrix. Besides, the grain refinement mechanism and behaviors were discussed.

scholarly journals Study of the Mechanical Properties of a Nanostructured Surface Layer on 316L Stainless Steel

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
F. C. Lang ◽  
Y. M. Xing ◽  
J. Zhu ◽  
Y. R. Zhao
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Surface Layer ◽  
Electron Microscope ◽  
316L Stainless Steel ◽  
Nanostructured Surface ◽  
Transmission Electron ◽  
Tensile Process ◽  
The Matrix ◽  
Reverse Analysis

A nanostructured surface layer (NSSL) was generated on a 316L stainless steel plate through surface nanocrystallization (SNC). The grains of the surface layer were refined to nanoscale after SNC treatment. Moreover, the microstructure and mechanical properties of NSSL were analyzed with a transmission electron microscope (TEM) and scanning electron microscope (SEM), through nanoindentation, and through reverse analysis of finite element method (FEM). TEM results showed that the grains in the NSSL measured 8 nm. In addition, these nanocrystalline grains took the form of random crystallographic orientation and were roughly equiaxed in shape. In situ SEM observations of the tensile process confirmed that the motions of the dislocations were determined from within the material and that the motions were blocked by the NSSL, thus improving overall yielding stress. Meanwhile, the nanohardness and the elastic modulus of the NSSL, as well as those of the matrix, were obtained with nanoindentation technology. The reverse analysis of FEM was conducted with MARC software, and the process of nanoindentation on the NSSL and the matrix was simulated. The plastic mechanical properties of NSSL can be derived from the simulation by comparing the results of the simulation and of actual nanoindentation.

Effect of a nanostructured surface layer on the tensile properties of 316L stainless steel

2013 ◽  
Vol 28 (10) ◽  
pp. 1311-1315 ◽  
Author(s):  
Pengfei Chui ◽  
Ouyang Jun ◽  
Yi Liu ◽  
Yanjie Liang ◽  
Yang Li ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Surface Layer ◽  
Tensile Properties ◽  
316L Stainless Steel ◽  
Nanostructured Surface ◽  
Image Position

Abstract

scholarly journals Microstructural Investigation of a Friction-Welded 316L Stainless Steel with Ultrafine-Grained Structure Obtained by Hydrostatic Extrusion

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1537
Author(s):  
Beata Skowrońska ◽  
Tomasz Chmielewski ◽  
Mariusz Kulczyk ◽  
Jacek Skiba ◽  
Sylwia Przybysz
Keyword(s):  
Stainless Steel ◽  
Electron Microscope ◽  
Friction Welding ◽  
High Speed ◽  
316L Stainless Steel ◽  
Welded Joint ◽  
Microstructural Investigation ◽  
Ultrafine Grained Structure ◽  
Ultrafine Grained ◽  
Friction Joint

The paper presents the microstructural investigation of a friction-welded joint made of 316L stainless steel with an ultrafine-grained structure obtained by hydrostatic extrusion (HE). Such a plastically deformed material is characterized by a metastable state of energy equilibrium, increasing, among others, its sensitivity to high temperatures. This feature makes it difficult to weld ultra-fine-grained metals without losing their high mechanical properties. The use of high-speed friction welding and a friction time of <1 s reduced the scale of the weakening of the friction joint in relation to result obtained in conventional rotary friction welding. The study of changes in the microstructure of individual zones of the friction joint was carried out on an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and electron backscattered diffraction (EBSD) analysis system. The correlation between the microstructure and hardness of the friction joint is also presented. The heat released during the high-speed friction welding initiated the process of dynamic recrystallization (DRX) of single grains in the heat-affected zone (HAZ). The additional occurrence of strong plastic deformations (in HAZ) during flash formation and internal friction (in the friction weld and high-temperature HAZ) contributed to the formation of a highly deformed microstructure with numerous sub-grains. The zones with a microstructure other than the base material were characterized by lower hardness. Due to the complexity of the microstructure and its multifactorial impact on the properties of the friction-welded joint, strength should be the criterion for assessing the properties of the joint.

Fabrication and Characterization of Nanostructured Surface Layer of 38CrSi Steel

2007 ◽  
Author(s):  
Shi-Ning Ma ◽  
De-Ma Ba ◽  
Chang-Qing Li ◽  
Fan-Jun Meng
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Surface Layer ◽  
Grain Refinement ◽  
Fine Particles ◽  
Nanostructured Surface ◽  
Cell Structures ◽  
Strain And Strain Rate ◽  
Transmission Electron ◽  
Average Grain Size

A nanocrystalline surface layer was fabricated on a 38CrSi Steel with tempered sorbite structure by using Supersonic Fine Particles Bombarding (SFPB). The microstructural evolution of SFPB-treated specimens under different processing conditions was characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Experimental evidence showed severe plastic deformation and obvious grains refinement were observed and a nanocrystalline surface layer (grain size < 100nm) was found after SFPB treatment. The thickness of nanostructured surface layer varies from a few to about 25μm as treated time increasing from 80s to 240s, but the grain size varies slightly. For the sample treated for 240s, the average grain size of equiaxed nanocrystallites with random crystallographic orientations on the top surface layer is about 16nm. The indexing of diffraction rings indicates nanostructured surface layer consists of ferrite and cementite phases without any evidence of a new phase. The structure size increases gradually from nano-scale to original-scale with an increase of the distance from the top surface layer. In the region about 20–30μm deep from the top surface, the microstructures are mainly composed of 60–100nm roughly equiaxed grains and subgrains. Some subbounsaries are composed of dense dislocation walls (DDWs). In this regime some cell structures are also seen, which are separated by dislocation lines (DTs) and some DDWs. Experimental analysis indicate coarse-grains are gradually refined into nano-sized grains by dislocations activity with gradual increase of strain and strain rate from matrix to treated surface. Both ferrite and cementite phases occur grain refinement. Grain refinement of 38CrSi sample is mainly attributed to the movement of dislocation.

Surface Nanocrystallization by Surface Mechanical Attrition Treatment

2008 ◽  
Vol 579 ◽  
pp. 91-108 ◽  
Author(s):  
N.R. Tao ◽  
Jian Lu ◽  
K. Lu
Keyword(s):  
Surface Layer ◽  
Grain Refinement ◽  
Mechanical Twinning ◽  
Surface Mechanical Attrition Treatment ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Tensile Fatigue ◽  
Mechanical Attrition ◽  
And Performance ◽  
Mechanical Twins

Based on strain-induced grain refinement, a novel surface mechanical attrition treatment (SMAT) technique has been developed to synthesize a nanostructured surface layer on metallic materials in order to upgrade their overall properties and performance without changing their chemical compositions. In recent several years, the microstructures and properties of surface layer were systematically investigated in various SMAT metals and alloys, including b.c.c., f.c.c. and h.c.p. crystal structures. Different grain refinement approaches and nanocrystalline formation mechanisms were identified in these deformed materials, involving dislocation activities, mechanical twinning and interaction of dislocations with mechanical twins. The properties of the surface layer were measured by means of hardness, tensile, fatigue and wear tests. The enhanced properties of the surface layer are mainly attributed to the strain-induced grain refinement. In this work, we reviewed the microstructures and properties of surface layer in the SMAT materials.

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