Crystallography of grain boundary proeutectoid ferrite

1975 ◽  
Vol 6 (7) ◽  
pp. 1419-1429 ◽  
Author(s):  
A. D. King ◽  
T. Bell
Keyword(s):  
Grain Boundary ◽  
Proeutectoid Ferrite

Three-Dimensional Observation and Growth Kinetics of Proeutectoid Ferrite Formed at Austenite Grain Boundary in a Low Carbon Microalloyed Steel

2007 ◽  
Vol 539-543 ◽  
pp. 4578-4583 ◽  
Author(s):  
Kai Ming Wu ◽  
A.M. Guo ◽  
Lin Cheng
Keyword(s):  
Grain Boundary ◽  
Growth Kinetics ◽  
Three Dimensional ◽  
Low Carbon ◽  
Austenite Grain ◽  
Ferrite Allotriomorphs ◽  
Proeutectoid Ferrite ◽  
Carbon Microalloyed ◽  
Austenite Grain Boundary ◽  
Kinetics Of

Three-dimensional observations of proeutectoid ferrite formed at grain boundary in an Fe-0.09%C-1.48%Mn vanadium microalloyed alloy was revealed by techniques of serial sectioning along with computer-aided reconstruction. The ferrite allotriomorphs nucleated at grain boundary edges were approximately prolate ellipsoids. Not all the ferrite allotriomorphs formed at grain boundary faces were oblate ellipsoids. The growth kinetics of ferrite allotriomorphs nucleated at grain boundary edges was greater than that of ferrite allotriomorphs nucleated at grain boundary faces.

The Effects of a High Magnetic Field on Microstructure, Grain Boundary Structures and Texture in a Medium Carbon Steel under Different Cooling Rates

2005 ◽  
Vol 495-497 ◽  
pp. 1261-1266
Author(s):  
Yu Dong Zhang ◽  
G. Vincent ◽  
Chang Shu He ◽  
X. Zhao ◽  
Liang Zuo ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Carbon Steel ◽  
Grain Boundary ◽  
Plain Carbon Steel ◽  
Medium Carbon Steel ◽  
Field Direction ◽  
Cooling Rates ◽  
Medium Carbon ◽  
Proeutectoid Ferrite ◽  
The Magnetic Field

A 12-Tesla magnetic field was applied during the transformation from austenite to ferrite and then pearlite in a medium plain carbon steel at two different cooling rates. Results show that when cooling is slow, the magnetic field shows an effect of promoting proeutectoid ferrite grains to grow along the field direction that results in an elongated grain microstructure. However, when cooling is fast, the magnetic field mainly shows an effect of reducing the amount of low angle misorientations and increasing the amount of CSL boundaries. In addition, the magnetic field exhibits a slight enhancement of the <001> texture component in the direction that is perpendicular to the field direction (TFD).

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Two Investigations into Grain Boundary Structure

1977 ◽  
Vol 35 ◽  
pp. 688-691
Author(s):  
P. Humble
Keyword(s):  
Grain Boundary ◽  
Dark Field ◽  
Boundary Structure ◽  
Boundary Dislocation ◽  
Bright Field ◽  
Intrinsic Structure ◽  
Weak Beam ◽  
Grain Boundary Structure ◽  
Independent Information ◽  
Diffraction Patterns

There has been sustained interest over the last few years into both the intrinsic (primary and secondary) structure of grain boundaries and the extrinsic structure e.g. the interaction of matrix dislocations with the boundary. Most of the investigations carried out by electron microscopy have involved only the use of information contained in the transmitted image (bright field, dark field, weak beam etc.). Whilst these imaging modes are appropriate to the cases of relatively coarse intrinsic or extrinsic grain boundary dislocation structures, it is apparent that in principle (and indeed in practice, e.g. (1)-(3)) the diffraction patterns from the boundary can give extra independent information about the fine scale periodic intrinsic structure of the boundary.In this paper I shall describe one investigation into each type of structure using the appropriate method of obtaining the necessary information which has been carried out recently at Tribophysics.

Metallurgical Effects of Grain Boundary Ledges

1977 ◽  
Vol 35 ◽  
pp. 126-129
Author(s):  
L.E. Murr
Keyword(s):  
Grain Boundary ◽  
Quantitative Data ◽  
Mechanical Treatment ◽  
Unit Length ◽  
Physical And Mechanical Properties ◽  
Direct Observations ◽  
Transmission Electron ◽  
Properties Of Materials ◽  
Thermo Mechanical Treatment ◽  
Ledge Density

Ledges in grain boundaries can be identified by their characteristic contrast features (straight, black-white lines) distinct from those of lattice dislocations, for example1,2 [see Fig. 1(a) and (b)]. Simple contrast rules as pointed out by Murr and Venkatesh2, can be established so that ledges may be recognized with come confidence, and the number of ledges per unit length of grain boundary (referred to as the ledge density, m) measured by direct observations in the transmission electron microscope. Such measurements can then give rise to quantitative data which can be used to provide evidence for the influence of ledges on the physical and mechanical properties of materials.It has been shown that ledge density can be systematically altered in some metals by thermo-mechanical treatment3,4.

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