scholarly journals Fabrication and Nanostructured Surface Layers of Al Alloy by Surface Vibrational Mechanical Attrition

2001 ◽  
Vol 697 ◽  
Author(s):  
X. Wu ◽  
Y. Hong ◽  
J. Lu ◽  
K. Lu
Keyword(s):  
Processing Time ◽  
Al Alloy ◽  
Nanostructured Surface ◽  
Surface Layers ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
Boundary Rotation ◽  
Nano Grains ◽  
Nanometer Regime ◽  
Simultaneous Evolution

AbstractNanograins were introduced into the surface layers of an Al-alloy during surface vibrational mechanical attrition. Transmission electron microscopy revealed that microstructures developed with an increase in strain, in the following sequence, i.e., lamellar microbands of elongated subgrains, equiaxed submicro-, and nano-grains respectively. The grain subdivision into the subgrains was found to be the main mechanism responsible for grain refinement. The simultaneous evolution of high boundary misorientations was ascribed to the boundary rotation for accommodating further strains. Results showed that the grains could refine remarkably into the nanometer regime (<100 nm) within the outer surface of the layer. The depth of the nanocrystal layers increased and the grain size decreased with the extension of processing time. The nanocrystal layers evidenced an increase in hardness.

Microstructure and Properties of Surface Nanostructured Copper

2011 ◽  
Vol 328-330 ◽  
pp. 1606-1609
Author(s):  
Wan Ming Lin ◽  
Yin Hui Wei ◽  
Li Feng Hou
Keyword(s):  
Copper Plate ◽  
Surface Mechanical Attrition Treatment ◽  
Hardness Testing ◽  
Surface Layers ◽  
Materials Properties ◽  
Transmission Electron ◽  
Mechanical Attrition ◽  
The Matrix ◽  
Novel Method ◽  
Potentiodynamic Anodic Polarization

Surface nanocrystallization (SNC) is a novel method for improving materials properties. Nanostructured surface layers of about 20 μm thickness were produced in copper plate samples by means of surface mechanical attrition treatment (SMAT). The behaviors of the SMAT samples were investigated by using transmission electron microscopy (TEM), Vickers hardness testing and potentiodynamic anodic polarization tests. The experimental results showed that the longer the peening time was performed on the copper pate samples, the thicker the deformation layers formed. The microhardness results for the top surface layer of the copper plate sample are 1.723 GPa and 1.752 GPa for 45 and 60 min, respectively, which are about two times higher than that of the matrix. The primary passivate potential of nanocrystalline copper was more negative than that of coarse-grain copper.

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.

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.

Processing of nanostructured metals and alloys via plastic deformation

MRS Bulletin ◽  
2010 ◽  
Vol 35 (12) ◽  
pp. 977-981 ◽  
Author(s):  
Yuntian Zhu ◽  
Ruslan Z. Valiev ◽  
Terence G. Langdon ◽  
Nobuhiro Tsuji ◽  
Ke Lu
Keyword(s):  
Plastic Deformation ◽  
High Pressure Torsion ◽  
Metals And Alloys ◽  
Surface Mechanical Attrition Treatment ◽  
Nanostructured Surface ◽  
Surface Layers ◽  
Nanostructured Metals ◽  
Angular Pressing ◽  
Mechanical Attrition ◽  
Processing Techniques

Plastic deformation can effectively produce nanostructured metals and alloys in bulk or surface-layer forms that are suitable for practical structural or functional applications. Such nanostructured materials are porosity-free and contamination-free, and therefore they are ideal for studying fundamental mechanisms and mechanical properties. In this article, we first give an overview of the principles of grain refinement by plastic deformation and an introduction to the reported processing techniques. Then the four most-developed and promising techniques will be described in detail: equal-channel angular pressing, high-pressure torsion, accumulative roll bonding for bulk nanostructured metals, and surface mechanical attrition treatment for nanostructured surface layers.

scholarly journals The Influence of Scandium on the Composition and Structure of the Ti-Al Alloy Obtained by “Hydride Technology”

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 918
Author(s):  
Natalia Karakchieva ◽  
Olga Lepakova ◽  
Yuri Abzaev ◽  
Victor Sachkov ◽  
Irina Kurzina
Keyword(s):  
Rietveld Method ◽  
Al Alloy ◽  
Surface Strength ◽  
Average Width ◽  
Near Surface ◽  
X Ray ◽  
Lamellar Structures ◽  
Quantitative Content ◽  
Transmission Electron ◽  
Composition And Structure

In this study the influence of scandium on the structural and phase state of the Ti-Al alloy obtained by the method of “Hydride Technology” (HT). The Rietveld method has allowed for determining the content of basic phases of the 49at.%Ti-49at.%Al-2at.%Sc system. By means of the methods of transmission electron microscopy (TEM) and X-ray spectral microanalysis, it has been established that scandium additives into the Ti-Al system result in the change of the quantitative content of phases in local regions of the structure. The Ti2Al5 phase has been found, and Ti2Al has been absent. In the morphology of substructures Ti-Al and Ti-Al-Sc there are lamellar structures or lamellae; the peculiarities of the distribution, fraction and size of which are influenced by scandium additives. The average width of Al-rich lamellae has been 0.85 µm, which is four times greater than that for the Ti-Al system (0.21 µm). For Ti-rich lamellae of the sample of the Ti-Al-Sc alloy, the average width of the lamellae has been 0.54 µm, and for Ti-Al it has been 0.34 µm. Based on the obtained data, a scheme of the distribution of phases in the composition of the Ti-Al-Sc alloy in the lamellar structures has been proposed. It has been established that in the Ti-Al-Sc system there is growth of the near-surface strength relative to Ti-Al. In this way, the microhardness of the Ti-Al-Sc alloy has amounted to 1.7 GPa, that is of the Ti-Al alloy which is 1.2 GPa.

scholarly journals Investigation of Zirconium Effect on the Corrosion Resistance of Aluminum Alloy Using Electrochemical Methods and Numerical Simulation in an Acidified Synthetic Sea Salt Solution

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1982 ◽  
Author(s):  
Yong-Sang Kim ◽  
Jong Park ◽  
Byeong-Seon An ◽  
Young Lee ◽  
Cheol-Woong Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Galvanic Corrosion ◽  
Sea Salt ◽  
Al Alloy ◽  
Alloying Element ◽  
Intermetallic Particles ◽  
Transmission Electron ◽  
Corrosion Simulation

Corrosion resistance of Zr that has been added to an Al alloy (U1070) is higher than that of a commercial Al alloy (A1070). A decreasing number and size of Al3Fe intermetallic particles (IMPs) were observed by electron microprobe analysis and transmission electron microscopy. Based on the numerical corrosion simulation, it was confirmed that decreasing the number and size of IMPs was favorable for improving the corrosion resistance of the Al alloy due to the reduction of the galvanic effect. In addition, Al3Zr was found to be insignificant in promoting galvanic corrosion within the Al matrix. Thus, Zr is an advantageous alloying element for improving the corrosion resistance of the Al alloy.

The Structure and Properties of Boundaries in Bicrystals of Boron-Doped Ni3(Al,l at% Ta)

1990 ◽  
Vol 213 ◽  
Author(s):  
M. J. Mills ◽  
S. H. Goods ◽  
S. M. Foiles
Keyword(s):  
Room Temperature ◽  
Tensile Ductility ◽  
Al Alloy ◽  
Boron Doped ◽  
Transmission Electron ◽  
Temperature Heat ◽  
Atomistic Calculations ◽  
Rate Of Cooling ◽  
Temperature Heat Treatment ◽  
Ductile State

ABSTRACTThe effect of boron on the structure and macroscopic properties of an isolated grain boundary in bicrystals of a non-stoichiometric Ni3Al alloy (76 at% Ni, 23 at% Al, 1 at%Ta) has been studied. The room temperature tensile ductility and fracture mode of the bicrystals varies dramatically with the rate of cooling after elevated temperature heat treatment. In the absence of significant segregation of boron to the boundary, the bicrystals fail via brittle interfacial fracture with little or no ductility. When the segregation of boron to the boundary is maximized, the bicrystals are highly ductile. High resolution transmission electron microscopy reveals that this ductile state is achieved without the formation of a detectable region of compositional disorder at the boundary. Atomistic calculations using a Monte Carlo scheme predict that only partial disordering of the planes immediately adjacent to the boundary should occur for Ni-rich alloys both with and without boron. These results suggest that the presence of boron causes an increase in the cohesive energy of the boundaries rather than a change in the local compositional ordering.

The effect of ageing duration on the mechanical properties of Al alloy 6061-garnet composites

2001 ◽  
Vol 215 (2) ◽  
pp. 113-119
Author(s):  
S C Sharma
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Al Alloy ◽  
Destructive Testing ◽  
Transmission Electron ◽  
Heat Treated ◽  
The Matrix ◽  
Reinforcing Particle ◽  
Alloy 6061

A well-consolidated composite of Al alloy 6061 reinforced with 4, 8 and 12 wt% garnet was prepared by a liquid metallurgy technique, the composite was heat treated for different ageing durations (T6 treatment), and its mechanical properties were determined by destructive testing. The results of the study indicated that, as the garnet particle content in the composites increased, there were marked increases in the ultimate tensile strength, compressive strength and hardness but there was a decrease in the ductility. There was an improvement in the tensile strength, compressive strength, and hardness with ageing due to precipitation. Precipitation in Al alloy 6061, with and without garnet particulate reinforcement, was studied using transmission electron microscopy. The fracture behaviour of the composites was altered significantly by the presence of garnet particles and the crack propagation through the matrix, and the reinforcing particle clusters resulted in final fracture.

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