Physical models for cleavage fracture at various temperatures - Bases for local approach to fracture of HSLA steel
Physical models for cleavage fracture at various temperatures - Bases for local approach to fracture of HSLA steel
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DOI：
10.1016/j.msea.2007.09.012
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发表时间：
2008-06-15
期刊：
影响因子：
6.4
通讯作者：
Chen, J. H.
中科院分区：
文献类型：
--
作者：
Chen, J. H.
作者提出了在不同温度下控制解理的临界事件：在很低的温度(-196℃)，临界事件是铁素体中裂纹在裂纹尖端的形核。在中等低温下(约-100摄氏度)，临界事件是碳化物裂纹扩展到铁素体晶内。随着温度的升高(在-80℃附近)，有可能扩展到铁素体晶内的碳化物裂纹应该是由高于低温碳化物裂纹临界应变的碳化物裂纹引起的。较高的临界应变通过加工硬化来增加流动应力，以弥补降低屈服应力的作用。在更高的温度下(-30℃)，当裂纹尖端钝化到60微米以上，纤维状裂纹扩展后，解理断裂的临界事件是晶粒度裂纹的扩展。(C)2007 Elsevier B.V.保留所有权利。
The author proposes the critical events controlling cleavage at various temperatures: at a very low temperature (- 196 degrees C), critical event is the nucleation of a crack in ferrite at the precrack tip. At a moderate low temperature (around - 100 degrees C), the critical event is the propagation of a carbide crack into the ferrite grain. With increasing temperature (around DBTT similar to-80 degrees C), the carbide crack eligible to propagate into the ferrite grain should be the one initiated by a critical strain higher than that to initiate a carbide crack at low temperatures. The higher critical strain increases the flow stress by work hardening for making up the effect of lowering yield stress. At a higher temperature (-30 degrees C) after the crack tip is blunted to more than 60 mu m and a fibrous crack extends, the critical event for cleavage fracture is the propagation of a grain-sized crack. (C) 2007 Elsevier B.V. All rights reserved.