Silver Self-Diffusion in Al2O3/QE22 Magnesium Alloy Matrix Composite

2009 ◽  
Vol 283-286 ◽  
pp. 155-160
Author(s):  
Ivo Stloukal ◽  
Jiří Čermák
Keyword(s):  
Magnesium Alloy ◽  
Temperature Dependence ◽  
Temperature Interval ◽  
Matrix Composite ◽  
Diffusion Coefficients ◽  
Volume Diffusion ◽  
Effective Diffusion ◽  
Measured Temperature ◽  
Alloy Matrix ◽  
Self Diffusion

Self-diffusion of 110mAg has been investigated in fiber reinforced QE22 magnesium alloy matrix composite. Short Saffil fibers (97% -Al2O3 + 3% SiO2) were used as reinforcement. The diffusion measurements were carried out in the temperature interval 648 – 728 K by serial sectioning method. The volume diffusion coefficients Dv (alloy without reinforcement) and the effective diffusion coefficients Deff (alloy with reinforcement) were obtained by analysis of the penetration curves. The silver diffusion coefficient in the interface boundary matrix/Saffil Di was also estimated. The temperature dependence of volume diffusion coefficients Dv was compared with previous data measured using 65Zn in the same alloy and with literature data for Zn impurity diffusion in Mg single crystal. It was observed, that the temperature dependence of both Deff and Di was significantly non-linear in the measured temperature interval. This behavior supports previous observations with zinc diffusion in the same alloy.

Diffusion of 65Zn in AZ91 and QE22 Alloys with Saffil Reinforcement-Influence of Interfaces Matrix/Saffil

2009 ◽  
Vol 289-292 ◽  
pp. 145-152
Author(s):  
Ivo Stloukal ◽  
Jiří Čermák
Keyword(s):  
Temperature Interval ◽  
Diffusion Coefficients ◽  
Volume Diffusion ◽  
Effective Diffusion ◽  
Measured Temperature ◽  
Elastic Stresses ◽  
Effective Diffusion Coefficients ◽  
Sectioning Method ◽  
The Matrix ◽  
Zinc Diffusion

Diffusion of 65Zn in two commercial Mg-based alloys AZ91 and QE22 with short Saffil fibers was studied. Experiments were carried out in the temperature interval 648 – 728 K by serial sectioning method. The effective diffusion coefficients Deff were compared with 65Zn diffusion coefficients Dv obtained with the same alloys without Saffil fibers. The evaluation of the influence of the interface between the matrix and the fibers upon Deff was done and the zinc diffusion coefficient Di in the interface boundary matrix/Saffil was estimated. Unlike the Arrhenius-like behavior of volume diffusion in both alloys, it was observed that the temperature dependence of both Deff and Di was significantly concave in the measured temperature interval. This behavior was attributed to relaxation of thermo-elastic stresses in the composite induced by a large difference between coefficients of thermal expansion (CTE) of Saffil fibers and metal matrix. The maximum values of Deff and Di, respectively, lie close to 693 K, where CTE has a minimum.

A magnesium alloy matrix composite reinforced with metallic glass

2009 ◽  
Vol 69 (15-16) ◽  
pp. 2734-2736 ◽  
Author(s):  
D.V. Dudina ◽  
K. Georgarakis ◽  
Y. Li ◽  
M. Aljerf ◽  
A. LeMoulec ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Metallic Glass ◽  
Matrix Composite ◽  
Alloy Matrix

Wear performance of TiC as reinforcement of a magnesium alloy matrix composite

2011 ◽  
Vol 42 (2) ◽  
pp. 275-279 ◽  
Author(s):  
L. Falcon-Franco ◽  
E. Bedolla-Becerril ◽  
J. Lemus-Ruiz ◽  
J.G. Gonzalez-Rodríguez ◽  
R. Guardian ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Matrix Composite ◽  
Alloy Matrix ◽  
Wear Performance

Surface treatment of Al18B4O33 whisker and development of Al18B4O33/ZK60 magnesium alloy matrix composite

2007 ◽  
Vol 187-188 ◽  
pp. 429-432 ◽  
Author(s):  
G. Sasaki ◽  
W.G. Wang ◽  
Y. Hasegawa ◽  
Y.B. Choi ◽  
N. Fuyama ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Surface Treatment ◽  
Matrix Composite ◽  
Alloy Matrix ◽  
Zk60 Magnesium Alloy

Zinc Self-Diffusion in ZnO

2005 ◽  
Vol 237-240 ◽  
pp. 163-168 ◽  
Author(s):  
M.A.N. Nogueira ◽  
Antônio Claret Soares Sabioni ◽  
Wilmar Barbosa Ferraz
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Diffusion Coefficients ◽  
Boundary Diffusion ◽  
Volume Diffusion ◽  
Grain Boundary Diffusion ◽  
Polished Surface ◽  
Self Diffusion ◽  
Zinc Diffusion ◽  
Diffusion Profiles

This work deals with the study of zinc self-diffusion in ZnO polycrystal of high density and of high purity. The diffusion experiments were performed using the 65Zn radioactive isotope as zinc tracer. A thin film of the tracer was deposited on the polished surface of the samples, and then the diffusion annealings were performed from 1006 to 1377oC, in oxygen atmosphere. After the diffusion treatment, the 65Zn diffusion profiles were established by means of the Residual Activity Method. From the zinc diffusion profiles were deduced the volume diffusion coefficient and the product dDgb for the grain-boundary diffusion, where d is the grain-boundary width and Dgb is the grain-boundary diffusion coefficient. The results obtained for the volume diffusion coefficient show good agreement with the most recent results obtained in ZnO single crystals using stable tracer and depth profiling by secondary ion mass spectrometry, while for the grain-boundary diffusion there is no data published by other authors for comparison with our results. The zinc grain-boundary diffusion coefficients are ca. 4 orders of magnitude greater than the volume diffusion coefficients, in the same experimental conditions, which means that grain-boundary is a fast path for zinc diffusion in polycrystalline ZnO.

Self-Diffusion in Isotopically Controlled Heterostructures of Elemental and Compound Semiconductors

1998 ◽  
Vol 527 ◽  
Author(s):  
H. Bracht ◽  
E. E. Haller ◽  
K. Eberl ◽  
M. Cardona ◽  
R. Clark-Phelps
Keyword(s):  
Temperature Dependence ◽  
Diffusion Coefficients ◽  
Secondary Ion Mass Spectrometry ◽  
Activation Enthalpy ◽  
Exponential Factor ◽  
Self Diffusion ◽  
Diffusion Studies ◽  
Exponential Factors ◽  
Secondary Ion ◽  
Diffusion Profiles

ABSTRACTWe report self-diffusion studies of silicon between 855 and 1388°C in highly enriched epitaxial 28Si layers. Diffusion profiles of 30Si and 29Si are determined with high resolution secondary ion mass spectrometry (SIMS). The temperature dependence of the Si self-diffusion coefficients is accurately described with an activation enthalpy of 4.76 eV and a pre-exponential factor of 560 cm2s-1. The single activation enthalpy indicates that Si self-interstitials dominate self-diffusion over the whole temperature range investigated. Self- and interdiffusion in buried Al71GaAs/Al69GaAs/71GaAs isotope heterostructures with different Al composition is measured between 800 and 1160°C. Ga self-diffusion in AlGaAs and interdiffusion of Al and Ga at the AlGaAs/GaAs interface show that Ga diffusion decreases with increasing Al composition and that the interdiffusion coefficient depends linearly on Al concentration. Furthermore Al is found to diffuse more rapidly into GaAs than Ga diffuses in GaAs. The temperature dependence of Ga and Al diffusion in GaAs and of Ga diffusion in AlGaAs is described by a single activation enthalpy in the range of 3.6±0.1 eV, but by different pre-exponential factors. Differences found for Ga and Al diffusion in GaAs and for Ga diffusion in AlGaAs with different Al concentrations are discussed.

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