Effects of grain boundary misorientation on the solute segregation in austenitic stainless steels

1998 ◽  
Vol 258-263 ◽  
pp. 2064-2068 ◽  
Author(s):  
T.S. Duh ◽  
J.J. Kai ◽  
F.R. Chen ◽  
L.H. Wang
Keyword(s):  
Grain Boundary ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Solute Segregation ◽  
Boundary Misorientation ◽  
Grain Boundary Misorientation

Anisotropic Grain Boundary Segregation in Y-Doped TiO2

2001 ◽  
Vol 7 (S2) ◽  
pp. 280-281
Author(s):  
G. D. Lian ◽  
A. Susalla ◽  
E. C. Dickey
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Level Structure ◽  
Boundary Segregation ◽  
Solute Segregation ◽  
Grain Boundary Segregation ◽  
Boundary Misorientation ◽  
Mole Percent ◽  
Dielectric System ◽  
Grain Boundary Misorientation

A variety of properties of polycrystalline TiO2, such as conductivity, creep and grain boundary diffusion, are strongly dependent on the atomic-level structure and chemistry of grain boundaries. TiO2 has been studied as a model dielectric system because of its relatively simple structure and well-understood point defect chemistry. Defect segregation in grain boundaries of polycrystalline and bi-crystal TiO2 have been studied by several groups and significant variations in solute segregation levels from boundary to boundary were observed. in this paper, we address this issue of anisotropic grain boundary segregation. We have measured solute segregation as a function of grain boundary misorientation to determine any correlation between segregation and misorientation.Yttria-doped TiO2 polycrystalline samples were prepared by mixing 99.999% pure TiO2 powder with 0.1% mole percent 99.99% purity Y(NO3)3 (both powders are commercially available from Aldrich Co. or Alfa Co.), followed by uni-axial pressed to 200-400Pa and sintering at 1300 °C for about 5-7 hours.

Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

1991 ◽  
Vol 49 ◽  
pp. 604-605
Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D. Matlock
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Stress Corrosion Cracking ◽  
Stainless Steels ◽  
Deformation Twin ◽  
Austenitic Stainless Steels ◽  
Carbide Precipitation ◽  
Strain Induced Martensite ◽  
Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

Measurement of solute segregation to grain boundaries in the AEM: A review

1988 ◽  
Vol 46 ◽  
pp. 606-607
Author(s):  
D. B. Williams ◽  
A. D. Romig
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Boundary Misorientation ◽  
Collector Plate ◽  
Segregation Process ◽  
Grain Boundary Misorientation ◽  
Structure Boundary ◽  
Equilibrium Segregation

The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).

Influence of Phosphorus Grain Boundary Segregation on Fracture Behaviour of Iron-Base Alloys

2007 ◽  
Vol 567-568 ◽  
pp. 33-38
Author(s):  
Jozef Janovec ◽  
Jaroslav Pokluda ◽  
Pavel Lejček
Keyword(s):  
Grain Boundary ◽  
Intergranular Fracture ◽  
Stainless Steels ◽  
Structural Changes ◽  
Fracture Behaviour ◽  
Boundary Segregation ◽  
Austenitic Stainless Steels ◽  
Grain Boundary Segregation ◽  
Boundary Concentration ◽  
Factors Influencing

Chemical and structural changes at the grain boundaries were investigated to quantify their influence on fracture behaviour of austenitic stainless steels and model ferritic Fe-Si-P alloys. The balance between the size and the area density of intergranular particles was found to be one of the most decisive factors influencing sensitivity of the steels to intergranular fracture. The precise dependence of the energy of intergranular fracture on the phosphorus grain boundary concentration was also determined.

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