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

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.

2007 ◽  
Vol 353-358 ◽  
pp. 1810-1813 ◽  
Author(s):  
Xiao Hua Yang ◽  
Wei Zhen Dui ◽  
Gang Liu

The mechanical properties of the 316L stainless steel subjected to surface mechanical attrition treatment (SMAT) have been studied, these properties are hardness, tensile properties and wear resistance. The research shows that the thickness of the hardened layer increases with the increasing of the treating time. The refined microstructure in the treated layer led to increasing in hardness, strength, and wear resistance. It is obvious that the surface layer hardness and bulk yield strength are increasing when the SMAT time reaches 5 minutes. The increase of surface layer wear resistance is obvious when the SMAT time is 15 minutes. The SEM observation of the wear scars shows that the nanocrystalline layer might reduce the effect of adhesive wear of 316L stainless steel. Therefore, the wear mechanism changes from adhesive abrasion to grinding particle abrasion after SMAT.


2013 ◽  
Vol 28 (10) ◽  
pp. 1311-1315 ◽  
Author(s):  
Pengfei Chui ◽  
Ouyang Jun ◽  
Yi Liu ◽  
Yanjie Liang ◽  
Yang Li ◽  
...  

Abstract


2011 ◽  
Vol 682 ◽  
pp. 115-119 ◽  
Author(s):  
Ling Zhu ◽  
Xin Min Fan

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.


Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1537
Author(s):  
Beata Skowrońska ◽  
Tomasz Chmielewski ◽  
Mariusz Kulczyk ◽  
Jacek Skiba ◽  
Sylwia Przybysz

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.


2020 ◽  
Author(s):  
Valentina A. Moskvina ◽  
Galina G. Maier ◽  
Kamil N. Ramazanov ◽  
Roman S. Esipov ◽  
Aleksey A. Nikolaev ◽  
...  

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