Dislocation Dipoles Observed in Alpha Brass
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概要
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Two kinds of dislocation dipoles have so far been reported by various authors. The one corresponding to a Taylor lattice consists of rows of closely spaced dislocations of opposite sign on the primary slip planes. The other is a long, narrow plus-minus pair lying along [112] in (111) plane. Some formation mechanisms of such a pair have been proposed and the possibillity that it becomes a closed prismatic loop has also been pointed out. In this short note other kinds of dislocation dipoles observed on deformed alpha brass are reported. Recently H. Suzuki has discussed the various processes of the formation of dislocation dipoles in connection with work-hardening. According to him parallel arrangements of dislocation dipoles are formed when the dislocations moving on successive slip Planes intersect a forest of screw dislocations. Fig. 1 shows parallel groups of dislocation dipoles observed on alpha brass extended 2 per cent and subsequently subjected to alternating bending stress. Similar patterns though not so clear have frequently been observed on statically deformed as well as on fatigued alpha brass. These arrangements may be due to the mechanism proposed by H. Suzuki. On the one hand, the presence of dislocation dipoles which contain the Frank-sessile type stacking fault has recently been proposed, from the measurements of residual resistivity of aluminium deformed at low temperatures by Takamura et al, who have emphasized the important role of sessile dipoles on the workhardening of f.c.c. metals. The formation of such sessile dipoles can be expected from the fine structure of a dislocation jog proposed by Hirsch and Weertman. Many long dislocation loops nearly parallel to each other can be seen in Fig. 2, which was obtained with alpha brass fatigued by alternating bending stress. Fringe contrast indicates that they contain stacking faults inside them. These loops, therefore, may probably be originated from the Frank-sessile dipoles mentioned above.
- 社団法人日本物理学会の論文
- 1964-06-05
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関連論文
- Anomaly Observed in Boundary-and Stacking-Fault-Fringes
- Change in the Crystal Orientation due to Dislocation Array on Slip Plane
- Dislocation Dipoles Observed in Alpha Brass