Positron Annihilation & Micro-Hardness Measurement of 6063 and 6066 with Compromise with Ingot Al

2010 ◽  
Vol 295-296 ◽  
pp. 39-47 ◽  
Author(s):  
M.A. Abdel-Rahman ◽  
Alaa Aldeen Ahmed ◽  
Emad A. Badawi
Keyword(s):  
Positron Annihilation ◽  
Vickers Hardness ◽  
Hardness Measurement ◽  
Micro Hardness ◽  
Quenching Temperature ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime ◽  
Different Temperatures ◽  
Hardness Values ◽  
Knoop Indenter

The aim of this work was to study the resistance of this type of alloy to quenching. Hardness measurements can be defined as macro-, micro- or nano- scale, according to the forces applied and the displacements obtained. This effect can also be studied using a nuclear, (PALT): positron annihilation lifetime, technique [1]. Microhardness is the hardness of a material, as determined by forcing an indenter such as a Vickers or Knoop indenter into the surface of the material under a 15 to 1000gf load; the indentations are usually so small that they must be measured using a microscope. These samples were quenched at different temperatures ranging from 50 to 500oC. We studied the effect of the quenching temperature upon the hardness measurements. We also studied this variation via the positron annihilation (lifetime) parameter. It is clear from the Vickers hardness that 1050 has the lowest value of Hv, while 6063 is higher and 6066 has the highest values of Hv. Also we could observe ( recognize) that the Hv (number) is reduce as a function of temperature (6066) but for (1050) and (6063) there is no observation of a variation in Hv (number) as a function of quenching temperature. The same observation was also made for 1050, 6063 and 6066 via the lifetime measurements. Here, 6063, 6066 give higher values than 1050. It is clear that the data from both techniques (positron annihilation lifetime and Vickers hardness) for 1050 ingot Al gives lower values of both parameters for Hv and lifetime technique. While Hv for 6066 is higher than the values of 6063 alloy at the same quenching temperature. Using the lifetime technique, one cannot distinguish between the 6063 and 6066 alloys. The applied force has no real effect upon the levels of the hardness values. Also, alloys 6066 and 6063 were defined as heat-treatable alloys but 1050 is not a heat-treatable alloy. The Hv of the 1050 is not affected by the changes in quenching temperature. Alloy 6066 heat-treatable alloy is more affected by the heat treatment than is 6063 alloy, and this is related to the structure of the precipitates in these alloys since 6066 alloy has much more Si and Mg than does the 6063 alloy. The Hv values vary from 14 to 23.9 for 6063 alloy and from 15.7 to 69.8 for 6066 alloy; in comparison with ingot alloy (1050) where it varies from 10.4 to 18.6.

Hydroformability of Bulge Forming Light-Weight Tubes via Micro-Hardness Dependence

2011 ◽  
Vol 465 ◽  
pp. 149-152
Author(s):  
G.D. Wang ◽  
Luen Chow Chan
Keyword(s):  
Vickers Hardness ◽  
Tube Hydroforming ◽  
Hardness Measurement ◽  
Light Weight ◽  
Micro Hardness ◽  
Forming Process ◽  
Material Hardness ◽  
Before And After ◽  
Hardness Values ◽  
Tubular Components

To evaluate the hydroformablility of tubular components in the tube hydroforming (THF) process, the conventional method is to measure the deformed square or circle grids printed on the surface of the tubular parts. However, the reliability of those measured data is affected greatly by the grid size and its measurement method on the curved surface. It is well-known that material hardness varies under different plastic deformation conditions, especially before and after the forming process. And it is more convenient to obtain the Vickers’ hardness values and distribution around the burst area of deformed components. This paper mainly presents an effective and reliable approach to evaluate the hydroformability of tubular components using micro-hardness measurement. At first, the Vickers’ hardness values and distribution around the burst area of the deformed components were obtained. The plastic strain, together with its distribution in such an area could then be derived by the measured micro-hardness through the developed equations. As a result, it was found to be more suitable to evaluate the hydroformability of tubes using this approach instead of the traditional grids measurement.

Testing Natural Aging Effect on Properties of 6066 & 6063 Alloys Using Vickers Hardness and Positron Annihilation Lifetime Techniques

2010 ◽  
Vol 303-304 ◽  
pp. 107-112
Author(s):  
M.A. Abdel-Rahman ◽  
Alaa Aldeen Ahmed ◽  
Emad A. Badawi
Keyword(s):  
Positron Annihilation ◽  
Vickers Hardness ◽  
Natural Aging ◽  
High Strength ◽  
Aging Effect ◽  
Hardness Measurement ◽  
Solution Temperature ◽  
Positron Annihilation Lifetime ◽  
Solid Diffusion ◽  
Maximum Value

The aim of this work was to produce a high strength 6xxx series Aluminum alloy by adjusting the processing conditions, namely solutionizing and natural aging. It consists of heating the alloy to a temperature at which the soluble constituents will form a homogeneous mass by solid diffusion, holding the mass at that temperature until diffusion takes place, then quenching the alloy rapidly to retain the homogeneous condition. In the quenched condition, heat-treated alloys are supersaturated solid solutions that are comparatively soft and workable, and unstable, depending on composition. At room temperature, the alloying constituents of some alloys tend to precipitate from the solution spontaneously, causing the metal to harden in about four days. This is called natural aging. The mechanical characterization of heat treatable 6xxx (Al-Mg-Si-Cu based) 6066, 6063 wrought aluminum alloys was studied. Their effects were investigated in terms of microstructure using positron annihilation lifetime technique and mechanical properties by hardness measurements. The hardness is the Resistance of material to plastic deformation, which gives it the ability to resist deformed when a load is applied. The greater the hardness of the material, the greater resistance it has to deformation. Hardness measurement can be defined as macro-, micro- or nano- scale according to the forces applied and displacements obtained. Micro hardness is the hardness of a material as determined by forcing an indenter such as a Vickers indenter into the surface of the material under 15 to 1000 gf load; usually, the indentations are so small that they must be measured with a microscope. During this work we are monitoring the effect of natural aging on the properties of positron lifetime and Vickers hardness parameters. The Vickers hardness of 6066 alloy has a maximum value(80) after (10)days of quenching at 530 which is the solution temperature of this alloy .the hardness of 6063 alloy has a maximum value (40) after (14)days of quenching at 520 which is the solution temperature of this alloy. The hardness which is conformed to the references.

Seeking the Good Fitting Procedure of PALS Polymer Spectra

2008 ◽  
Vol 607 ◽  
pp. 64-66
Author(s):  
Nicolas Laforest ◽  
Jérémie De Baerdemaeker ◽  
Corine Bas ◽  
Charles Dauwe
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Positron Annihilation ◽  
Physical Meaning ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime ◽  
Fitting Procedure ◽  
Fitting Procedures ◽  
Blob Model

Positron annihilation lifetime measurements on polymethylmethacrylate (PMMA) at low temperature were performed. Different discrete fitting procedures have been used to analyze the experimental data. It shows that the extracted parameters depend strongly on the fitting procedure. The physical meaning of the results is discussed. The blob model seems to give the best annihilation parameters.

Positron Annihilation Lifetime Measurements in Collagen Biopolymer

1998 ◽  
Vol 530 ◽  
Author(s):  
S. Siles ◽  
G. Moya ◽  
X.H. Li ◽  
J. Kansy ◽  
P. Moser
Keyword(s):  
Positron Annihilation ◽  
Amorphous Region ◽  
Positron Annihilation Spectroscopy ◽  
Lifetime Data ◽  
Spectroscopy Technique ◽  
Lifetime Measurements ◽  
Lifetime Distributions ◽  
Positron Annihilation Lifetime ◽  
Coincidence System ◽  
Three Components

AbstractLifetime measurement in Positron Annihilation Spectroscopy (PAS) is applied to the study of free-volume collagen characteristics as a function of concentration. The lifetimes of positrons were obtained by a conventional fast-fast coincidence system. All lifetime data are fitted in three components by using the computer program POSITRON FIT and resolved. For each concentration, lifetime distributions were analyzed in order to obtain the different components, thus we have observed three components of which a long component τ3. This long lived component can be associated with a pick-off annihilation of ortho-positronium (o-Ps) trapped in free volumes of amorphous region. This investigation shows the potential of the positron annihilation spectroscopy technique in the study of biopolymer microstructures.

Positron Annihilation Spectroscopic Studies of Cu2Te Thermoelectric Material

2017 ◽  
Vol 373 ◽  
pp. 231-236
Author(s):  
Wen Na Ge ◽  
Ju Ping Xu ◽  
Run Ye ◽  
Jian Dang Liu ◽  
Bang Jiao Ye
Keyword(s):  
Positron Annihilation ◽  
Thermoelectric Material ◽  
Surface Defects ◽  
Total Concentration ◽  
Spectroscopic Studies ◽  
Positron Annihilation Lifetime ◽  
Ratio Spectrum ◽  
S Parameter ◽  
Different Temperatures ◽  
Defect Species

Positron annihilation lifetime spectroscopy (PALS) and coincident Doppler-broadening spectroscopy (CDBS) have been used for investigating the evolution of vacancy-type defects in the thermoelectric material Cu2Te which annealed at different temperatures. The results of PALS show that a fraction of positrons has got annihilated at the surfaces and the sample which annealed at 450 °C has the highest concentration of surface defects. The average positron lifetime and the S parameter have the same trends which gradually increase with the increase of the annealing temperature. This change implies that the total concentration of the defects has been changed with the change of the annealed temperatures. The results of the CDBS ratio spectrum and S-W plot indicate that the defect species have no change after annealing at different temperatures.

Positron annihilation lifetime measurements of mechanically fatigued polystyrene samples

2008 ◽  
Vol 46 (18) ◽  
pp. 1991-1995 ◽  
Author(s):  
J. Erichsen ◽  
C. Nagel ◽  
K. Günther-Schade ◽  
M. Renner ◽  
V. Altstädt ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime

scholarly journals POSITRON LIFETIME MEASUREMENTS IN NATURAL RUBBER WITH DIFFERENT FILLERS

2013 ◽  
Vol 22 ◽  
pp. 112-117 ◽  
Author(s):  
A. MANDAL ◽  
S. MUKHERJEE ◽  
S. PAN ◽  
A. SENGUPTA
Keyword(s):  
Natural Rubber ◽  
Positron Annihilation ◽  
Free Volume ◽  
Positron Lifetime ◽  
Amorphous Region ◽  
Filler Concentration ◽  
Lifetime Measurements ◽  
Positron Annihilation Lifetime

Positron annihilation lifetime spectra (PLAS) have been measured for natural rubber polymer with different fillers (Titenium dioxide, Nanosilica and Nanoclay) as a function of filler concentration to investigate how these fillers affect the microstructure of free volume of natural rubber. The lifetime spectra is analyzed by using LT9.0 and the longest lived component(τo-Ps) is attributed to the pick- off annihilation of o-Ps in free volume sites, available mostly in the amorphous region of polymer. On the basis of the τo-Ps values the radii of the free volume holes (Rh) are calculated. The PALS results show that o-Ps lifetime as well as the size of free volume decreases with the increase of filler concentration.

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