Thermodynamic Model for the Hysteresis in Metal-Hydrogen Systems.

Schwarz, R. B. ; Khachaturyan, A. G.

Technical Information Center Oak Ridge Tennessee

关键词: Hysteresis;    Thermodynamic model;    Free energy;    Transforming phases;    Quantitative expressions;   

RP-ID  :  DE2001763368

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

A phenomenon common to most metalhydrogen systems is the presence of hysteresis in their cyclic absorption/resorption characteristics. Because hysteresis on a reversible transformation is indicative of a dissipative mechanism, early models (1) attributed the hysteresis to the plastic deformation needed to accommodate the volume change upon hydride formation. A friction model, however, cannot explain the reproducibility of the hysteresis over thousand of cycles. We propose that the hysteresis is an intrinsic thermodynamic phenomenon caused by the coherency strains between the parent metal phase and the transformed hydride phase. In this paper, we summarize the salient features of the model and explain its relevance to known metalhydrogen systems.