Influence of Surface Mechanical Attrition Treatment Attrition Media on the Surface Contamination and Corrosion of Magnesium

CORROSION ◽  
10.5006/0763 ◽  
2012 ◽  
Vol 69 (6) ◽  
pp. 527-535 ◽  
Author(s):  
D. Fabijanic ◽  
A. Taylor ◽  
K.D. Ralston ◽  
M.-X. Zhang ◽  
N. Birbilis
Keyword(s):  
Grain Refinement ◽  
Surface Composition ◽  
Optical Emission ◽  
Surface Contamination ◽  
Grain Structure ◽  
Surface Mechanical Attrition Treatment ◽  
Ultrafine Grain ◽  
Surface Residual Stress ◽  
Mechanical Attrition ◽  
Steel Balls

Surface mechanical attrition treatment (SMAT) is a mechanical peening process used to generate ultrafine grain surfaces on a metal. SMAT was carried out on pure magnesium using different attrition media (zirconia [ZiO2], alumina [Al2O3], and steel balls) to observe the effect on microstructure, surface residual stress, surface composition, and corrosion. Surface contamination from SMAT was characterized using glow discharge optical emission spectroscopy (GDOES). The SMAT process produced a refined grain structure on the surface of Mg but resulted in a region of elemental contamination extending ~10 μm into the substrate, regardless of the media used. Consequently, SMAT-treated surfaces showed an increased corrosion rate compared to untreated Mg, primarily through increased cathodic kinetics. This study highlights the issue of contamination resulting from the SMAT process, which is a penalty that accompanies the significant grain refinement of the surface produced by SMAT. This must be considered if attempting to exploit grain refinement for improving corrosion resistance.

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.

An Effect of High Magnetic Field on Grain Growth in Nanocrystalline Iron

2007 ◽  
Vol 539-543 ◽  
pp. 2793-2797 ◽  
Author(s):  
W.P. Tong ◽  
L.M. Wang ◽  
G.J. Ma ◽  
N.R. Tao ◽  
Liang Zuo
Keyword(s):  
Magnetic Field ◽  
Grain Growth ◽  
High Magnetic Field ◽  
Early Stage ◽  
Grain Structure ◽  
Surface Mechanical Attrition Treatment ◽  
Iron Sample ◽  
Mechanical Attrition ◽  
Different Temperatures ◽  
Nanocrystalline Iron

A nanostructured surface layer on a pure iron sample was prepared by surface mechanical attrition treatment (SMAT). The thermal stability of SMAT sample was investigated at different temperatures with or without a high magnetic field (H =12T). It was found that a high magnetically annealing enhanced grain growth at the early stage of annealing, and produced a uniform nanocrystalline grain structure. After homogeneous grains developed, further grain growth became restrained.

scholarly journals A Coupled EBSD/TEM Analysis of the Microstructure Evolution of a Gradient Nanostructured Ferritic/Martensitic Steel Subjected to Surface Mechanical Attrition Treatment

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 140 ◽  
Author(s):  
Wenbo Liu ◽  
Xiao Jin ◽  
Bo Zhang ◽  
Di Yun ◽  
Piheng Chen
Keyword(s):  
Grain Boundaries ◽  
Transition Zone ◽  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Surface Region ◽  
Surface Mechanical Attrition Treatment ◽  
Ultrafine Grain ◽  
Tem Analysis ◽  
Mechanical Attrition ◽  
Rafm Steel

Surface mechanical attrition treatment (SMAT) was performed on a reduced ferritic/martensitic (RAFM) steel to form a nanostructured (NS) layer on the surface of the sample. Both electron backscatter diffraction (EBSD) and TEM were used to investigate the microstructure evolution during SMAT. The experimental results showed that there were three different zones after SMAT: (i) The “ultrafine grain” (UFG) zone, observed at the top-most surface region, (ii) the “transition zone” in which the original grains were fragmented under the severe plastic deformation and (iii) the “deformed zone” in which the original grains were simply deformed. The average grain sizes increased rapidly with the increase of depth, while the Vickers hardness decreased with the increase of depth, and this phenomenon could be explained in terms of boundary strengthening and dislocation strengthening. The number fractions of medium-angle grain boundaries (MAGBs) and medium-high-angle grain boundaries (MHAGBs) in UFG zones were larger than those in the transition zone and the deformed zone. However, the number fraction of the low-angle grain boundaries (LAGBs) was extremely small in all the zones after SMAT, especially in the transition zone.

Microstructural Evolution and Grain Refinement in a Cu-Zr Alloy Processed by High-Pressure Torsion

2014 ◽  
Vol 783-786 ◽  
pp. 2635-2640 ◽  
Author(s):  
Jittraporn Wongsa-Ngam ◽  
Terence G. Langdon
Keyword(s):  
High Pressure ◽  
Grain Refinement ◽  
Microstructural Evolution ◽  
High Pressure Torsion ◽  
Electron Backscatter Diffraction ◽  
Grain Morphology ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Refinement Mechanism ◽  
Ultrafine Grain Structure

A copper alloy, Cu-0.1% Zr, was processed at room temperature by high-pressure torsion (HPT) in order to evaluate the microstructural evolution and grain refinement mechanism. Transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) techniques were employed to measure the grain morphology, grain size distributions and the distribution of the misorientation angles. The results demonstrate that this processing procedure has a potential for producing an ultrafine-grain structure containing reasonably equiaxed grain with high-angle boundary misorientations. The grain refinement mechanism is primarily governed by dislocation activities.

Interface Microstructure of Diffusion Bonded Fe3Al/Al with Ultrafine Grain Layer

2010 ◽  
Vol 667-669 ◽  
pp. 1171-1175
Author(s):  
Jiang Wei Ren ◽  
Dong Li ◽  
Ai Dang Shan
Keyword(s):  
Transition Zone ◽  
Dissimilar Materials ◽  
Surface Mechanical Attrition Treatment ◽  
Ultrafine Grain ◽  
Atom Diffusion ◽  
Ultrafine Grains ◽  
Mechanical Attrition ◽  
Bonded Joint ◽  
Deformed Layer ◽  
Wide Transition

The influence of ultrafine grains produced by severe plastic deformation technology on the weldability of Fe3Al and Al dissimilar materials was investigated. An ultrafine grain layer was produced on Fe3Al intermetallic compound by surface mechanical attrition treatment. Then the SMATed Fe3Al was diffusion bonded with 1060Al at 550°C for 90 min in the vacuum of 10-3 Pa. The microstructures of surface ultrafine grain layer and transition zone at the interface of SMATed-Fe3Al/Al joint were observed by scanning electron microscopy. The grain size of surface ultrafine grains was characterized by X-ray diffractometry. The elements distribution at the interface and the phase constituents of transition zone were measured by energy disperse spectroscopy. The results showed that a deformed layer about 10-20 μm wide and surface nanocrystallines about 35nm were produced after 15 min surface mechanical attrition. SMATed Fe3Al was well bonded with Al and 11-30 µm wide transition zone formed. The transition zone consisted of FeAl and FeAl3 phases. The surface nanocrystallines helped the atom diffusion and the formation of diffusion bonded joint with rough surface and lower pressure.

Modelling of Grain Refinement Induced by SMAT Process, Using a Complete Numerical Chaining Methodology

2013 ◽  
Vol 762 ◽  
pp. 295-300
Author(s):  
Souhail Benafia ◽  
Delphine Retraint ◽  
Benoit Panicaud ◽  
Lea le Joncour ◽  
Emmanuelle Rouhaud ◽  
...  
Keyword(s):  
Finite Element ◽  
Grain Refinement ◽  
Material Properties ◽  
Element Model ◽  
Surface Mechanical Attrition Treatment ◽  
Metallic Materials ◽  
Element Analysis ◽  
Mechanical Attrition ◽  
Micromechanical Approach ◽  
The Impact

Surface Mechanical Attrition Treatment (SMAT) is a recent process that enables to nanocrystallise the surface of metallic alloys. It can thus enhance mechanical properties of the treated material by inducing a grain refinement down to the nanometre scale, in the top surface layer. This nanocrystallisation process leads to different effects that were successively studied on several metallic materials. In the present work, investigations are carried out on the modelling of SMAT. A simulation of the shot dynamics is performed using different process parameters, with the aim to obtain the impact velocity field on the treated surface. This field is then used as an input for a finite element model to predict the induced grain refinement. The evolution of the micro and nanostructures are then calculated using a micromechanical approach, which takes into account the dislocations and their interactions. Coupled with a finite element analysis, this approach enables to deduce the influence of the process on the macroscopic material properties, whatever the geometry of the sample.

Electrophoretic Deposition of Hydroxyapatite and 58S Bioactive Glass Coatings on the Ti6Al4V Alloy Subjected to Surface Mechanical Attrition Treatment

2015 ◽  
Vol 654 ◽  
pp. 149-153 ◽  
Author(s):  
Joël Faure ◽  
Richard Drevet ◽  
Nader Ben Jaber ◽  
Sylvain Potiron ◽  
Clémence Demangel ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Technical Problem ◽  
Ti6al4v Alloy ◽  
Surface Mechanical Attrition Treatment ◽  
Bioactive Glasses ◽  
Surface Scanning ◽  
X Ray ◽  
Mechanical Attrition ◽  
Spray Technique ◽  
Steel Balls

Hydroxyapatite (HAP) and 58S Bioactive Glasses (BG) coatings are successfully synthesized by Electrophoretic Deposition (EPD) on Ti6Al4V alloy subjected to Surface Mechanical Attrition Treatment (SMAT). This process uses steel balls impacts on the Ti6Al4V surface to improve its mechanical properties. However when the Ti6Al4V substrate is treated by SMAT the industrial plasma spray technique is not efficient to obtain adherent HAP coatings. This problem is mainly related to the modifications of the Ti6Al4V surface topography due to the SMAT process. Therefore, in this work we demonstrate that EPD offers an efficient solution to solve this technical problem. Indeed we obtain a homogeneous and adherent HAP coating on the SMATed Ti6Al4V surface from a suspension of nanoparticles in ethanol. Moreover EPD is successfully employed to produce a 58S BG coating on the SMATed Ti6Al4V surface. Scanning Electron Microscopy (SEM) associated to Energy Dispersive X-Ray Spectroscopy (EDXS) reveals that the coatings obtained by EPD are adherent and compact without alteration of their chemical composition.

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