Effect of loading history on the threshold stress in the creep deformation of an austenitic stainless steel
Effect of loading history on the threshold stress in the creep deformation of an austenitic stainless steel
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DOI：
10.1016/j.msea.2007.04.005
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发表时间：
2008-01
期刊：
影响因子：
6.4
通讯作者：
C. Shastry;P. Parameswaran;M. D. Mathew;K. B. S. Rao;S. Pathak
中科院分区：
文献类型：
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作者：
C. Shastry;P. Parameswaran;M. D. Mathew;K. B. S. Rao;S. Pathak
AISI 316L(N) SS在923K时的稳态蠕变速率可以用阈值应力补偿幂律关系来描述。在142-230MPa的应力范围内，蠕变变形的阈值应力用图形表示为常规蠕变试验的60±10MPa。通过两次应力降低试验计算得到的阈值应力约为110MPa，远高于常规蠕变试验结果。通过引用位错胞结构对稳态蠕变速率方程中常数A的影响来解释较高的表观阈值应力。应力变化试验中，应力逐渐增加，产生的阈值应力与从常规蠕变试验中获得的阈值应力相同。这意味着，只要前面的应力较低，在特定应力下的稳态结构是路径无关的。位错亚结构表明蠕变是通过位错网络机制进行的。该机制的阈应力表示构成Frank网络的位错链接激活的应力。
The steady state creep rate of AISI 316L(N) SS at 923K can be described by the threshold stress compensated power law relationship. The threshold stress for creep deformation over the stress range 142–230MPa has been evaluated graphically as 60±10MPa from the conventional creep tests. A threshold stress of about 110MPa was computed from two stress decrease tests which is much higher than that obtained from conventional creep tests. The higher apparent threshold stress has been rationalized by invoking the effect of dislocation cell structure on the constant A in the steady state creep rate equation. A stress change test wherein the stress was progressively increased yielded a threshold stress identical to that obtained from the conventional creep tests. This implies that the steady state structure at a particular stress is path independent so long as the preceding stresses are lower. The dislocation substructure indicates that the creep deformation proceeds by the dislocation network mechanism. The threshold stress for this mechanism represents the stress for the activation of dislocation links constituting the Frank network.