Abstract A procedure is developed that evaluates the energy dissipated from a material subject to cyclic loading and enables identification of the difference in material microstructure. It is demonstrated that the dissipated energy can be derived from specimens loaded in the elastic region using temperature measurements obtained by infrared thermography. To obtain accurate values of the small temperature changes resulting from the intrinsic dissipation below the yield point, a key part of the procedure is to eliminate the effect of external heat sources and sinks from the vicinity of the test specimen under investigation. To this end, a chamber was designed to minimise the external radiation whilst allowing the specimens to be cyclically loaded; the configuration of the chamber is described, alongside its integration into the procedure. A reference specimen was specifically introduced in the chamber to take into account the thermal exchanges between the specimen and the chamber environment. A data processing procedure, based on the thermomechanical heat diffusion equation, is applied to enable the dissipated energy to be derived from the temperature measurements. It is established that quantifying the amount of energy dissipation provides an opportunity to identify the material condition. The procedure is demonstrated on specimens made from 316L stainless steel containing a range of microstructures produced by different heat treatments. It is shown that the dissipative energy is dependent on the microstructure and that the dissipative source can be identified using the experimental procedure.

中文翻译：

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316L 不锈钢的显微结构评估使用基于红外热成像的循环加载引起的能量耗散测量

摘要 开发了一种评估材料在循环载荷下耗散的能量并能够识别材料微观结构差异的程序。结果表明，使用通过红外热成像法获得的温度测量值，可以从加载在弹性区域中的试样导出耗散能量。为了获得屈服点以下固有耗散导致的微小温度变化的准确值，该程序的一个关键部分是消除所研究试样附近的外部热源和散热器的影响。为此，设计了一个腔室以最大限度地减少外部辐射，同时允许样品循环加载；描述了腔室的配置，以及它与程序的集成。一个参考样品被专门引入腔室，以考虑样品与腔室环境之间的热交换。应用基于热机械热扩散方程的数据处理程序使耗散能量能够从温度测量中导出。已经确定，量化能量耗散量提供了识别材料状况的机会。该程序在由 316L 不锈钢制成的试样上进行了演示，该试样包含通过不同热处理产生的一系列微观结构。结果表明，耗散能量取决于微观结构，并且可以使用实验程序识别耗散源。