Life time and cyclic slip of copper in the VHCF regime
Life time and cyclic slip of copper in the VHCF regime
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DOI：
10.1016/j.ijfatigue.2007.03.010
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发表时间：
2007-09-01
影响因子：
6
通讯作者：
Schoenbauer, Bernd
中科院分区：
文献类型：
--
作者：
Stanzl-Tschegg, Stefanie;Mughrabi, Hael;Schoenbauer, Bernd
对多晶铜在极低循环应力幅和极高循环次数下的疲劳性能进行了研究。实验采用省时的超声疲劳技术进行。因此，可在合理的测试时间内进行超过10（10）次循环的实验。主要的结果是，低于PSB阈值，不可逆的循环滑移沿着晶面仍然发生，证明了在表面滑移线图案的变化下降到应变和应力幅值是低至约只有一半的PSB阈值。这些值被称为SB（滑带）阈值。在1 x 10（10）次循环以下，无法检测到传统意义上的疲劳极限。因此，定义了1 x 10（10）次循环的阈值（在本研究中称为疲劳寿命阈值），该阈值比PSB阈值高约50%。SB是否实际上是PSB或在PSB阈值以下持续循环是否最终导致PSB形成并在极长时间测试后最终失败的问题必须在未来的研究中回答。(C)2007爱思唯尔有限公司版权所有。
Studies were performed on the fatigue properties of polycrystalline copper at very low cyclic stress amplitudes and very high numbers of cycles. The experiments were carried out with the time-saving ultrasonic fatigue technique. Thus, experiments up to more than 10(10) cycles could be performed within reasonable testing time. Main result is that below the PSB threshold, irreversible cyclic slip along crystallographic planes still occurs, as evidenced by changes in the surface slip line pattern down to strain and stress amplitudes that are as low as approximately only half of the PSB threshold values. These values are named SB (slip band) thresholds. No fatigue limit in the conventional sense could be detected below 1 x 10(10) cycles. Thus, a threshold value at 1 x 10(10) cycles is defined (named fatigue life threshold in this study) which is roughly 50% higher than the PSB threshold. The question whether the SBs are actually PSBs or whether continued cycling below the PSB threshold would ultimately lead to PSB formation and finally failure after extremely long testing has to be answered in future studies. (C) 2007 Elsevier Ltd. All rights reserved.