Volume‐diffusion‐controlled shrinkage of an isolated grain‐boundary pore

1973 ◽  
Vol 44 (4) ◽  
pp. 1890-1892
Author(s):  
Alan J. Markworth
Keyword(s):  
Grain Boundary ◽  
Volume Diffusion ◽  
Diffusion Controlled

A TEM investigation of a hyper-eutectic lead-tin alloy

1988 ◽  
Vol 46 ◽  
pp. 562-563
Author(s):  
John A. Sutliff
Keyword(s):  
Volume Diffusion ◽  
Eutectic Mixture ◽  
Precipitation Reaction ◽  
Directionally Solidified ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffusion Controlled ◽  
Discontinuous Precipitation Reaction ◽  
Controlled Precipitation

Near-eutectic Pb-Sn alloys are important solders used by the electronics industry. In these solders, the eutectic mixture, which solidifies last, is the important microstructural consituent. The orientation relation (OR) between the eutectic phases has previously been determined for directionally solidified (DS) eutectic alloys using x-ray diffraction or electron chanelling techniques. In the present investigation the microstructure of a conventionally cast, hyper-eutectic Pb-Sn alloy was examined by transmission electron microscopy (TEM) and the OR between the eutectic phases was determined by electron diffraction. Precipitates of Sn in Pb were also observed and the OR determined. The same OR was found in both the eutectic and precipitation reacted materials. While the precipitation of Sn in Pb was previously shown to occur by a discontinuous precipitation reaction,3 the present work confirms a recent finding that volume diffusion controlled precipitation can also occur.Samples that are representative of the solder's cast microstructure are difficult to prepare for TEM because the alloy is multiphase and the phases are soft.

Interpretation of grain boundary grooving data for combined surface and volume diffusion

1975 ◽  
Vol 6 (8) ◽  
pp. 1653-1654 ◽  
Author(s):  
W. M. Robertson ◽  
S. R. Srinivasan
Keyword(s):  
Grain Boundary ◽  
Volume Diffusion

Mesoscale Simulations of Microstructure Evolution in a Temperature Gradient

2010 ◽  
Vol 1264 ◽  
Author(s):  
Bala Radhakrishnan ◽  
Gorti Sarma
Keyword(s):  
Temperature Gradient ◽  
Grain Boundary ◽  
Pore Size ◽  
Microstructure Evolution ◽  
Volume Diffusion ◽  
Grain Structure ◽  
Migration Direction ◽  
Boundary Force ◽  
Mesoscale Simulations ◽  
Model Approach

AbstractThe evolution of pore and grain structure in a nuclear fuel environment is strongly influenced by the local temperature, and the temperature gradient. The evolution of pore and grain structure in an externally imposed temperature gradient is simulated for a hypothetical material using a Potts model approach that allows for porosity migration by mechanisms similar to surface, grain boundary and volume diffusion, as well as the interaction of migrating pores with stationary grain boundaries. First, the migration of a single pore in a single crystal in the presence of the temperature gradient is simulated. Next, the interaction of a pore moving in a temperature gradient with a grain boundary that is perpendicular to the pore migration direction is simulated in order to capture the force exerted by the pore on the grain boundary. The simulations reproduce the expected variation of pore velocity with pore size as well as the variation of the grain boundary force with pore size.

Effect of Strong Magnetic Field on the Discontinuous and Continuous Precipitation in AZ91 Mg Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 849-852 ◽  
Author(s):  
Jie Dong ◽  
Z.F. Li ◽  
Xiao Qing Zeng ◽  
Chen Lu ◽  
Wen Jiang Ding
Keyword(s):  
Magnetic Field ◽  
Grain Boundary ◽  
Aging Process ◽  
Volume Diffusion ◽  
Discontinuous Precipitation ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Az91 Magnesium Alloy ◽  
Continuous Precipitation ◽  
Az91 Magnesium

A strong static magnetic field (SSMF) of about 10 T was introduced to the aging process of AZ91 magnesium alloy. Comparing with conventional aging, in the first stage of aging with SSMF, discontinuous precipitation of Mg17Al12 at grain boundary was accelerated. The magnetically induced grain boundary migration might be responsible for this acceleration effect. The density of the Mg17Al12 continuous precipitates inside the grains was increased and the precipitation plates became thinner in SSMF pre-aged specimens, which might be ascribed to the retarded volume diffusion resulted from the SSMF.

SELF-DIFFUSION IN POLYCRYSTALLINE NICKEL

1959 ◽  
Vol 37 (10) ◽  
pp. 1623-1628 ◽  
Author(s):  
J. R. MacEwan ◽  
J. U. MacEwan ◽  
L. Yaffe
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Volume Diffusion ◽  
Grain Boundary Diffusion ◽  
The Self ◽  
Polycrystalline Nickel ◽  
Self Diffusion ◽  
Diffusion Studies

The self-diffusion of nickel has been studied in polycrystalline samples by a sectioning technique. There is evidence of grain boundary diffusion below temperatures of 1150 °C. The results obtained between 1150° and 1400 °C are representative of volume diffusion and are represented by the expression[Formula: see text]A comparison is made with the results of other self-diffusion studies using Zener's hypothesis.

scholarly journals Mixed diffusion-controlled growth of pearlite in binary steel

2010 ◽  
Vol 467 (2126) ◽  
pp. 508-521 ◽  
Author(s):  
A. S. Pandit ◽  
H. K. D. H. Bhadeshia
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Growth Rate ◽  
Volume Diffusion ◽  
Controlled Growth ◽  
Mechanical Equilibrium ◽  
Interfacial Diffusion ◽  
Diffusion Controlled ◽  
Simplified Method ◽  
Transformation Front

A kinetic theory for the diffusion-controlled growth of pearlite is presented, which accounts simultaneously for diffusion through the austenite and via the transformation front. The simplified method abandons the need for mechanical equilibrium at the phase junctions and yet is able to explain experimental data on the growth rate of pearlite. Furthermore, unlike previous analyses, the deduced value for the activation energy for the interfacial diffusion of carbon is found to be realistic when compared with corresponding data for volume diffusion.

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