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This paper focuses on the fatigue life calculation for an unalloyed medium carbon steel SAE1045 (German DIN-standard: C45E), by applying an energy dissipation-based approach quantified through thermographic measurements. The purpose of this approach is to establish an intrinsic dissipation model and to predict characteristics derived from the cyclic deformation behavior of stress-controlled fatigue tests, eg, the fatigue limit and the S-N data by using simplified (zero-dimensional, 0D) thermodynamic equations. In order to investigate the possibilities for a rapid evaluation while simultaneously reducing the experimental effort, one load increase test (LIT) and two constant amplitude tests (CATs) were carried out. The S-N data evaluated on such a basis is competitive to conventionally determined S-N data as will be shown. K E Y W O R D Sfatigue life evaluation, intrinsic dissipation, medium carbon steel, thermography

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A nondestructive thermographic methodology is utilized to determine the fracture fatigue entropy for evaluating the fatigue damage in metals within the high-cycle fatigue regime. Thermodynamic entropy is shown to play an important role in the fatigue process to trace the fatigue damage as an irreversible degradation of a metallic material being subjected to cyclic elastic-plastic loading. This paper presents a method to evaluate fatigue damage in the normalized SAE 1045 steel being based on the concept of thermodynamic entropy and its nonlinearities. The procedure looks to be applicable to constant and load increase tests proven by experiments.

The syntheses of Ni-poor (NCM111, LiNi 1/3 Co 1/3 Mn 1/3 O 2 ) and Ni-rich (NCM811 LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) lithium transition-metal oxides (space group R3̅ m) from hydroxide precursors (Ni 1/3 Co 1/3 Mn 1/3 (OH) 2 , Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 ) are investigated using in situ synchrotron powder diffraction and near-edge X-ray absorption fine structure spectroscopy. The development of the layered structure of these two cathode materials proceeds via two utterly different reaction mechanisms. While the synthesis of NCM811 involves a rock salt-type intermediate phase, NCM111 reveals a layered structure throughout the entire synthesis. Moreover, the necessity and the impact of a preannealing step and a high-temperature holding step are discussed.

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