Microstructure and strain-stress analysis of the dynamic strain aging in inconel 625 at high temperature

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• 作者：P. Maj ; J. Zdunek ; J. Mizera ; K. J. Kurzydlowski…
• 关键词：mechanical properties ; activation analysis ; lattice defects ; plasticity ; strain aging
• 刊名：Metals and Materials International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：23
• 期：1
• 页码：54-67
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Metallic Materials; Operating Procedures, Materials Treatment; Magnetism, Magnetic Materials; Engineering Thermodynamics, Heat and Mass Transfer; Characterization and Evaluation of Materials; Continuu
• 出版者：The Korean Institute of Metals and Materials
• ISSN：2005-4149
• 卷排序：23

文摘

Serrated flow is a result of unstable plastic flow, which occurs during tensile and compression tests on some dilute alloys. This phenomenon is referred as the Portevin Le-Chatelier effect (PLC effect). The aim of this research was to investigate and analyze this phenomenon in Inconel 625 solution strengthened superalloy. The tested material was subjected to tensile tests carried out within the temperature range 200-700 °C, with three different strain rates: 0.002 1/s, 0.01/s, and 0.05 1/s and additional compression tests with high deformation speeds of 0.1, 1, and 10 1/s. The tensile strain curves were analyzed in terms of intensity and the observed patterns of serrations Using a modified stress drop method proposed by the authors, the activation energy was calculated with the assumption that the stress drops’ distribution is a direct representation of an average solute atom’s interaction with dislocations. Subsequently, two models, the standard vacancy diffusion Bilby-Cottrell model and the realistic cross-core diffusion mechanism proposed by Zhang and Curtin, were compared. The results obtained show that the second one agrees with the experimental data. Additional microstructure analysis was performed to identify microstructure elements that may be responsible for the PLC effect. Based on the results, the relationship between the intensity of the phenomenon and the conditions of the tests were determined.