The grain size dependence of flow and fracture in a Cr-Mn-N austenitic steel from 300 to 1300K
The grain size dependence of flow and fracture in a Cr-Mn-N austenitic steel from 300 to 1300K
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DOI：
10.1007/bf02673673
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
V. Rao;D. Taplin;P. Rao
中科院分区：
文献类型：
--
作者：
V. Rao;D. Taplin;P. Rao
在298-1273K温度范围内，研究了多晶晶尺寸在18-184µm范围内对21Cr14Mn0.68N-0.12C奥氏体不锈钢拉伸行为的影响。结果表明，在873K温度范围内，晶粒度的减小使小应变下的流动应力按Hall-Petch关系增大。特别是在低应变率下，霍尔-佩奇关联式发生了反转，流动应力随晶粒度的减小而减小。延性与温度的关系表现为在绝对熔化温度的一半左右延性最小，并观察到晶间空化现象。在此温度范围内，晶粒度的减小通常会增强延性，而在细晶粒度下，这一趋势则相反。这些结果可以用Griffith-Orowan断裂准则和沿晶空泡片断裂机制的组合来解释。
The influence of polycrystal grain size in the range 18 µm to 184 µm on the tensile behavior of an austenitic stainless steel containing by wt pct 21 Cr, 14 Mn, 0.68 N and 0.12 C has been investigated over the temperature range 298 to 1273 K. Decreasing grain size has been shown to increase the flow stress at small strains in accordance with the Hall-Petch relationship at temperatures up to 873 K. The variation of the Hall-Petch constants with temperature is influenced by dynamic strain ageing between 575 and 775 K. Above 875 K, especially at low strain-rates a reversal of the Hall-Petch correlation occurs and the flow stress decreases with decreasing grain size. The relationship between ductility and temperature is marked by a minimum ductility at about half the absolute melting temperature and intergranular cavitation is observed. A decrease in grain size generally enhanced the ductility in this temperature regime whilst at fine grain sizes this trend was reversed. These results are explained in terms of a combination of a Griffith-Orowan type fracture criterion and an intergranular void sheet mechanism of fracture.