検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年

粉末冶金モリブデン材の疲労変形による動的回復・再結晶挙動

Dynamic recovery and recrystallization behavior caused by fatigue for sintered molybdenum

西 宏; 榎枝 幹男; 河村 繕範

Nishi, Hiroshi; Enoeda, Mikio; Kawamura, Yoshinori

粉末冶金法により製造されるモリブデンやタングステンは、ボイド等の材料内部の欠陥を減少させるため、強度の熱間・温間圧延を行っている。そのため材料内部に蓄えられる蓄積エネルギーは高く、組織は不安定で、粉末冶金モリブデン材は再結晶温度以下でも高温疲労中に動的回復・再結晶を起こし材料は軟化する。本研究では、この高温疲労中に動的回復・再結晶による材料組織の変化を光学顕微鏡、透過型電子顕微鏡等を用い観察し、静的回復・再結晶と比較した。また動的回復・再結晶のメカニズムを明らかにするため、軟化の見かけの活性化エネルギーを求めた。その結果、軟化の見かけの活性化エネルギーは格子拡散の活性化エネルギーに比べ小さく,疲労変形中の拡散の活性化エネルギーは低下することが分かった。

Powder metallurgy molybdenum and tungsten received severe hot roll reduction after the sintering to reduce the internal defects such as voids. Hence these metals have high stored energy and show unstable microstructures. The molybdenum exhibits cyclic softening being caused dynamic recovery and recrystallization during high temperatures fatigue below its static recrystallization temperature. In this investigation, the observations of microstructures change during high temperatures fatigue are performed and compare to those of static recrystallization. Moreover, the apparent activation energy of the cyclic softening is evaluated to study the mechanisms of the dynamic recovery and recrystallization. The apparent activation energy of the cyclic softening is extremely lower than that of lattice diffusion of molybdenum and the activation energy of lattice diffusion is reduced during high temperatures fatigue.

Access

:

- Accesses

InCites™

:

Altmetrics

:

[CLARIVATE ANALYTICS], [WEB OF SCIENCE], [HIGHLY CITED PAPER & CUP LOGO] and [HOT PAPER & FIRE LOGO] are trademarks of Clarivate Analytics, and/or its affiliated company or companies, and used herein by permission and/or license.