Interface Diffusion in Cu Processed by Means of Surface Mechanical Attrition Treatment

2009 ◽  
Vol 289-292 ◽  
pp. 557-563 ◽  
Author(s):  
Z.B. Wang ◽  
K. Wang ◽  
K. Lu ◽  
Gerhard Wilde ◽  
Sergiy V. Divinski
Keyword(s):  
Grain Size ◽  
Surface Layer ◽  
Subsurface Layer ◽  
Coarse Grained ◽  
Surface Mechanical Attrition Treatment ◽  
Nanostructured Surface ◽  
Radiotracer Technique ◽  
Mechanical Attrition ◽  
The Difference ◽  
Effective Diffusivities

A nanostructured surface layer with a gradient microstructure was produced on a Cu plate by means of the surface mechanical attrition treatment (SMAT). Diffusion of Ni in the nanostructured layer was investigated by the radiotracer technique at temperatures from 383 to 438 K. The measured diffusion profiles consist of two distinct sections with different slopes, the steep one corresponding to the top surface layer with the grain size of 10 to 25 nm and the shallow one corresponding to a subsurface layer with a grain size of 25 to 100 nm. The effective diffusivities derived from both sections are more than 2 orders of magnitudes higher than the grain boundary diffusivities in coarse-grained Cu. The significantly accelerated diffusion rates are expected to be associated with the “non-equilibrium” states of interfaces in the nanostructured surface layer induced by SMAT. The difference between the diffusivities in the top and sub- surface layer might result from the fact that most interfaces developed from twin boundaries in the former while produced by dislocation activities in the latter.

Surface Nanocrystallines of Fe3Al Produced by Surface Mechanical Attrition

2011 ◽  
Vol 320 ◽  
pp. 325-328 ◽  
Author(s):  
Jiang Wei Ren ◽  
Dong Li ◽  
Pei Quan Xu
Keyword(s):  
Grain Size ◽  
Surface Layer ◽  
Surface Mechanical Attrition Treatment ◽  
Electronic Microscopy ◽  
X Ray ◽  
Structure And Morphology ◽  
Mechanical Attrition ◽  
Deformed Layer ◽  
Fe3al Intermetallic ◽  
Morphology Of Surface

A nanocrystallines surface layer was produced in Fe3Al intermetallic compound by surface mechanical attrition treatment (SMAT). The microstructure of deformed layer, phase structure and morphology of surface nanocrystallines were characterized through optical microscopy, X-ray diffractometry, transmission electronic microscopy and high resolution electronic microscopy. The results show that a deformed layer about 11μm wide is produced after 10min surface mechanical attrition. The grains on the top surface of Fe3Al are refined to nanocrystallines and the grain size of nanocrystallines is about 35nm. High density dislocations collect on the boundaries of grains. The formation of nanocrystallines is controlled by grain subdivision mechanism.

Wear Behaviour of Pure Ti with a Nanocrystalline Surface Layer

2011 ◽  
Vol 66-68 ◽  
pp. 1500-1504 ◽  
Author(s):  
Ming Wen ◽  
Cui'e Wen ◽  
Peter D. Hodgson ◽  
Yun Cang Li
Keyword(s):  
Grain Size ◽  
Wear Resistance ◽  
Titanium Surface ◽  
Pure Titanium ◽  
Coarse Grained ◽  
Surface Mechanical Attrition Treatment ◽  
Wear Behaviour ◽  
Wear Properties ◽  
Microstructure Observation ◽  
Mechanical Attrition

A nanocrystalline (NC) layer with the thickness of 30 µm was produced on pure titanium surface by surface mechanical attrition treatment (SMAT). Microstructure observation indicated that the grain size increases with depth from the treated surface. The friction coefficient decreases and the wear resistance increases with the SMAT sample as compared to its coarse-grained counterpart. The improvement of the wear properties could be attributed to the higher hardness of SMAT sample.

Study on the Structure and Properties of Surface Nanocrystallized Zr-4

2011 ◽  
Vol 415-417 ◽  
pp. 660-665
Author(s):  
Cong Hui Zhang ◽  
Da Li Liu ◽  
Xin Zhe Lan ◽  
Xi Cheng Zhao
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Processing Time ◽  
Optical Microscope ◽  
Surface Mechanical Attrition Treatment ◽  
Structure And Properties ◽  
Nanostructured Surface ◽  
Grain Sizes ◽  
Mechanical Attrition ◽  
Average Grain Size

A nanostructured surface layer was obtained on the surface of Zr-4 by surface mechanical attrition treatment(SMAT). The structure and the properties of the SMAT sample were analyzed by means of the optical microscope, hardness and polarization curve testing. The results show that， when processing time for 5min, the average grain sizes on the surface layer can be refined to 23nm. The average grain size by SMAT-ed for 15min is 20nm, which is the smallest. The microhardness have a significant increase, the surface roughness also increase, and the corrosion resistance reduce in 1mol H2SO4solution.

Diffusion of Cr in Nanostructured Fe and Low Carbon Steel Produced by Means of Surface Mechanical Attrition Treatment

2006 ◽  
Vol 249 ◽  
pp. 147-154 ◽  
Author(s):  
Z.B. Wang ◽  
N.R. Tao ◽  
W.P. Tong ◽  
Jian Lu ◽  
K. Lu
Keyword(s):  
Surface Layer ◽  
Carbon Steel ◽  
Steel Plate ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
Surface Mechanical Attrition Treatment ◽  
Low Carbon ◽  
Triple Junctions ◽  
Exponential Factor ◽  
Mechanical Attrition

By means of surface mechanical attrition treatment (SMAT), nanostructured (NS) surface layers were fabricated on a pure iron plate and a low carbon steel plate. Cr diffusion behaviors in the NS Fe phase and the SMAT low carbon steel were investigated. Experimental results showed the activation energy of Cr diffusion in the NS Fe is comparable to that of the GB diffusion, but the pre-exponential factor is much higher. A much thicker Cr-diffusion surface layer was obtained in the SMAT low carbon steel plate than in the coarse-grained one after the same chromizing treatment. The much enhanced diffusivities of Cr in the SMAT samples can be attributed to numerous GBs and triple junctions with a high excess stored energy in the NS surface layer.

scholarly journals MICROSTRUCTURE EVOLUTION AND DEFORMATION FEATURE OF AZ31 MAGNESIUM ALLOY DURING SEVERE PLASTIC DEFORMATION

2012 ◽  
Vol 06 ◽  
pp. 503-508
Author(s):  
LI-FENG HOU ◽  
YING-HUI WEI ◽  
XUE-FENG SHU
Keyword(s):  
Surface Layer ◽  
Magnesium Alloy ◽  
Microstructure Evolution ◽  
Az31 Magnesium Alloy ◽  
Surface Mechanical Attrition Treatment ◽  
Nanostructured Surface ◽  
Deformation Feature ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Refinement Process

A nanostructured surface layer was produced on commercially AZ31 magnesium alloy using surface mechanical attrition treatment (SMAT). The microstructure evolution and deformation feature along the depth of the treated surface layer were characterized by transmission electron microscope (TEM) investigations. The grain refinement process, accompanied by an increase in the surface layer, involves: the onset of twins; the formation of microbands associated with the dislocation slipping; the subdivision of microbands into low angle grains and then highly disoriented polygonal submicronic grains, and further breakdown into randomly oriented nanograins with progression of dynamic recrystallization.

Neutral Molten Salt-Bath Carburizing of Ti6Al4V Alloy with Nanocrystalline Surface Layer at Low Temperature Assisted by Surface Mechanical Attrition Treatment

2017 ◽  
Vol 727 ◽  
pp. 1001-1008 ◽  
Author(s):  
Quan Tong Yao ◽  
Wei Ping Tong ◽  
Meng Yao Li ◽  
Guang Lan Zhang
Keyword(s):  
Surface Layer ◽  
Low Temperature ◽  
Molten Salt ◽  
Salt Bath ◽  
Coarse Grained ◽  
Experimental Result ◽  
Surface Mechanical Attrition Treatment ◽  
Neutral Salt ◽  
Mechanical Attrition ◽  
Molten Salt Bath

Nanocrystalline surface layer about 10~15μm thick was fabricated on the surface of Ti6Al4V sheet by means of the surface mechanical attrition treatment (SMAT). The average grain size was about 10nm and the grain characteristic presented equiaxed morphology. The nanocrystalline surface layer could be perfectly maintained below 550°C in the following thermal stability analysis. Neutral salt mixture was about 21% NaCl, 31% BaCl2 and 48% CaCl2 and additionally 5% Na2CO3 of total was utilized. After carburizing process, a continuous charcoal grey carburized layer was composed of TiC and carbon supersaturated solid solution, the hardening layer was about 10~15μm thick. The hardness of the outermost surface reached 1000HV, which was much higher than its coarse-grained counterpart in the same carburizing condition. The experimental result indicated that the carburizing kinetics was obviously enhanced by nanocrystalline surface layer assistance. Furthermore, the neutral molten salt-bath carburizing was verified that it could be performed in a relatively low temperature of 650°C.

Thermal stability and corrosion resistance of nanocrystallized zirconium formed by surface mechanical attrition treatment

2009 ◽  
Vol 24 (10) ◽  
pp. 3136-3145 ◽  
Author(s):  
Yong Han ◽  
Lan Zhang ◽  
Jian Lu ◽  
Wengting Zhang
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Grain Growth ◽  
Coarse Grained ◽  
Surface Mechanical Attrition Treatment ◽  
Passive Protection ◽  
Mechanical Attrition ◽  
Nanostructured Layer ◽  
Pure Zirconium

The thermal stability and corrosion behavior of the nanostructured layer on commercially pure zirconium, produced by surface mechanical attrition treatment (SMAT), were investigated. It is indicated that the nanograined Zr is stable at annealing temperatures up to 650 °C, above which significant grain growth occurs and the grain size shows parabolic relationship with annealing time. The activation energy for grain growth of the nanograined Zr is 59 kJ/mol at 750–850 °C, and the grain growth is dominated by grain-boundary diffusion. The as-SMATed nanograined Zr exhibits higher corrosion resistance than the 550–750 °C annealed SMATed Zr and the unSMATed coarse-grained Zr. It is indicated that the corrosion resistance of Zr tends to increase with the reduction of grain size, which is related to the dilution of segregated impurities at grain boundaries due to grain refinement and the formation of passive protection film.

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