On the Portevin-Le Chatelier Effect Due to Snoek Strain Aging in the Niobium Oxygen System
On the Portevin-Le Chatelier Effect Due to Snoek Strain Aging in the Niobium Oxygen System
复制标题
铌氧系统中 Snoek 应变老化引起的 Portevin-Le Chatelier 效应
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
R. Reed
中科院分区：
文献类型：
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作者：
S. C. Park;L. Beckerman;R. Reed
在含0.01 ~ 0.95at.在77 ~ 971 K温度范围内，采用8.8 × 10-5 s-1的名义应变速率，研究了10%氧对应变速率的影响。在355 ~ 422 K的高氧浓度下，观察到A型和B型锯齿。有人提出，所有这些锯齿形的流动是由于Snoek动态应变时效。这是由锯齿的外观在比通常与科特雷尔应变老化和观察到的应力应变曲线上的A型锯齿之间的时间等于氧原子的跳跃时间低得多的温度下支持的。应变率敏感性测量结果与普遍接受的观点一致，即只有当应变率敏感性变得足够负时才会出现锯齿。
Dynamic strain aging in niobium containing between 0.01 and 0.95 at. pct oxygen was investigated between 77 and 971 K using a nominal strain rate of 8.8 × 10-5 s-1. At higher oxygen concentrations both type A and type B serrations were observed between 355 and 422 K. It is proposed that all of this serrated flow is due to Snoek dynamic strain aging. This is supported by the appearance of the serrations at much lower temperatures than those normally associated with Cottrell strain aging and the observation that the time between the type A serrations on a stress strain curve equals the jump time of an oxygen atom. Strain rate sensitivity measurements were consistent with the generally accepted view that serrations occur only when the strain rate sensitivity becomes sufficiently negative.