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■■■■■■■■■■■■■■■■■■■ 川崎製鉄技報 KAWASAKI STEEL GIHO Vol.4 (1972) No.3 ■■■■■■■■■■■■■■■■■■■ |
| 鉄−３wt％ニッケル多結晶体のリューダース変形 Luders Deformation in Iron ― 3wt% Nickel Polycrystals 田中 智夫(Tomoo Tanaka) |
| 要旨 : 鉄−３wt％ニッケル多結晶体を用いてLuders bandの発生，伝播，加工硬化域での変形の挙動を調べた。Pre-yield領域での応力緩和テストの結果delayed yieldがおこり，それに伴なって試験片の応力集中部にLuders bandが発生することがわかった。定歪速度試験から得られる活性化パラメータはLuders bandの伝播，均一変形の領域で単一の熱活性化過程が支配的であることを示す。応力緩和テストから得られる転位速度―応力指数m*はLuders 変形，加工硬化の領域で同一の値を示す。これらの結果はLuders bandの発生に関しては固着雰囲気からの転位の解放の過程が律速段階であろうことを示すが，bandの伝播と加工硬化域での変形は転位の動的な性質に支配されるであろうことを示す。 |
| Synopsis : An investigation was made on the initiation and propagation of Luders band and flow in the region of work hardening in annealed iron ― 3wt% nickel polycrystals. Stress relaxation test in pre-yield region showed delayed yield, accompanied by the formation of Luders band which was triggered at the stress-concentrated region. Activation analysis showed that a single thermally activated dislocation mechanism may be rate controlling during the propagation of Luders band and flow in work hardening region. By means of relaxation test, the same value for dislocation velocity-stress exponent m* was obtained over the whole range of strain including Luders and work hardening region. These observations strongly suggest that Luders band is initiated by release of dislocation from Cottrell atmosphere as proposed by Fisher, whereas, its propagation and flow in work hardening region are controlled by the dynamical behavior of dislocations. |
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