What types of grain boundaries can be passed through by persistent slip bands?

2003 ◽  
Vol 18 (5) ◽  
pp. 1031-1034 ◽  
Author(s):  
Z. F. Zhang ◽  
Z. G. Wang ◽  
J. Eckert
Keyword(s):  
Grain Boundaries ◽  
Large Angle ◽  
Fatigue Cracking ◽  
Stress Axis ◽  
Slip Systems ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
Different Types ◽  
The Difference ◽  
Intergranular Fatigue Cracking

Three typical interactions of persistent slip bands (PSBs) with different types of grain boundaries (GBs) were investigated and analyzed in fatigued copper crystals. The results show that PSBs cannot transfer through all types of large-angle GBs, regardless of their orientation with respect to the stress axis. Secondary slip was often observed near the GBs, leading to strain incompatibility. When the slip systems of the two adjacent crystals are coplanar, the transmission of a PSB across a GB strongly depends on the slip directions of the two adjacent crystals. It was found that only the low-angle GBs can be passed through by PSBs, and accordingly they are insensitive to intergranular fatigue cracking. For a special copper bicrystal with coplanar slip systems, the ladderlike dislocation arrangements within the adjacent PSBs become discontinuous and a dislocation-affected-zone appears near the GB due to the difference in the slip direction of the two adjacent crystals. Therefore, the necessary conditions for the transmission of a PSB across a GB are that the neighboring grains have a coplanar slip system and identical slip directions.

Observation of secondary slip systems in tungsten bicrystals

1984 ◽  
Vol 42 ◽  
pp. 478-479
Author(s):  
J. R. Fekete ◽  
R. Gibala
Keyword(s):  
Stress Field ◽  
Grain Boundaries ◽  
Deformation Behavior ◽  
Stress Axis ◽  
Polycrystalline Materials ◽  
Slip Systems ◽  
Metallic Materials ◽  
Twist Boundary ◽  
Secondary Slip ◽  
Plane Normal

The deformation behavior of metallic materials is modified by the presence of grain boundaries. When polycrystalline materials are deformed, additional stresses over and above those externally imposed on the material are induced. These stresses result from the constraint of the grain boundaries on the deformation of incompatible grains. This incompatibility can be elastic or plastic in nature. One of the mechanisms by which these stresses can be relieved is the activation of secondary slip systems. Secondary slip systems have been shown to relieve elastic and plastic compatibility stresses. The deformation of tungsten bicrystals is interesting, due to the elastic isotropy of the material, which implies that the entire compatibility stress field will exist due to plastic incompatibility. The work described here shows TEM observations of the activation of secondary slip in tungsten bicrystals with a [110] twist boundary oriented with the plane normal parallel to the stress axis.

Distinct fatigue cracking modes of grain boundaries with coplanar slip systems

2016 ◽  
Vol 120 ◽  
pp. 120-129 ◽  
Author(s):  
L.L. Li ◽  
Z.J. Zhang ◽  
P. Zhang ◽  
J.B. Yang ◽  
Z.F. Zhang
Keyword(s):  
Grain Boundaries ◽  
Fatigue Cracking ◽  
Slip Systems ◽  
Cracking Modes

The Half-Cycle Slip Activity of Persistent Slip Bands in Polycrystals

2007 ◽  
Vol 567-568 ◽  
pp. 123-127 ◽  
Author(s):  
A. Weidner ◽  
W. Tirschler ◽  
C. Blochwitz ◽  
Werner Skrotzki
Keyword(s):  
Volume Fraction ◽  
Half Cycle ◽  
Slip Systems ◽  
Large Scatter ◽  
Force Microscopy ◽  
Atomic Force ◽  
Slip Bands ◽  
Slip Activity ◽  
Persistent Slip Bands ◽  
Number Of Cycles

The development of the volume fraction of cumulated persistent slip bands (PSBs) in cyclically deformed nickel polycrystals was investigated in dependence on the number of cycles using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was shown that there is a large scatter of the volume fraction of PSBs from grain to grain. Three different tendencies for the development of the volume fraction with increasing number of cycles were distinguished. It was shown that there is a correlation of the orientation of the primary slip systems with the volume fraction of cumulated PSBs and the activation of PSBs during half-cycle deformation.

Orientation Evolutions During Hot Rolling of Electrical Steel Containing Initial Columnar Grains

2011 ◽  
Vol 702-703 ◽  
pp. 754-757 ◽  
Author(s):  
Ping Yang ◽  
Y.Y. Shao ◽  
W.M. Mao ◽  
Q.W. Jiang ◽  
W.X. Jin
Keyword(s):  
Grain Boundaries ◽  
Hot Rolling ◽  
Electrical Steel ◽  
Texture Evolution ◽  
Center Layer ◽  
Different Types ◽  
Columnar Grains ◽  
The Difference ◽  
Ebsd Technique ◽  
Hot Rolled

The texture evolution in the surface and center layer of hot rolled electrical steel containing initial columnar grains with their <100> nearly along ND, RD and TD of sheets were determined by EBSD technique. The transition from Goss to Brass or Copper orientation in surface was analyzed. The difference in texture of center layers in these samples was compared. In particular, orientation evolutions within grains and at grain boundaries of different types of orientations were explored. The results are discussed in terms of the special alignments of grain boundaries among columnar grains.

Ex and in situ investigations on the role of persistent slip bands and grain boundaries in fatigue crack initiation

2017 ◽  
Vol 32 (23) ◽  
pp. 4276-4286 ◽  
Author(s):  
Heinz Werner Höppel ◽  
Philip Goik ◽  
Christian Krechel ◽  
Mathias Göken
Keyword(s):  
Fatigue Crack ◽  
Crack Initiation ◽  
Grain Boundaries ◽  
Fatigue Crack Initiation ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
Image Position

Abstract

The initial fatigue crack

1957 ◽  
Vol 242 (1229) ◽  
pp. 189-197 ◽  
Keyword(s):  
Fatigue Crack ◽  
Grain Boundaries ◽  
Low Temperatures ◽  
Room Temperature ◽  
Fatigue Cracks ◽  
Slip Bands ◽  
Persistent Slip Bands

A discussion is given of the formation of persistent slip bands during cyclic stressing and their development into fatigue cracks. In copper and in aluminium at low temperatures fatigue cracks appear to be formed in this way; at room temperature in aluminium they may form also along grain boundaries.

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