Heat Capacity And Thermal Expansion At Low Temperatures

The birth of this monograph is partly due to the persistent efforts of the General Editor, Dr. Klaus Timmerhaus, to persuade the authors that they encapsulate their forty or fifty years of struggle with the thermal properties of materials into a book before they either expired or became totally senile. We recognize his wisdom in wanting a monograph which includes the closely linked properties of heat capacity and thermal expansion, to which we have added a little 'cement' in the form of elastic moduli. There seems to be a dearth of practitioners in these areas, particularly among physics postgraduate students, sometimes temporarily alleviated when a new generation of exciting materials are found, be they heavy fermion compounds, high temperature superconductors, or fullerenes. And yet the needs of the space industry, telecommunications, energy conservation, astronomy, medical imaging, etc. , place demands for more data and understanding of these properties for all classes of materials - metals, polymers, glasses, ceramics, and mixtures thereof. There have been many useful books, including Specific Heats at Low Tempera tures by E. S. Raja Gopal (1966) in this Plenum Cryogenic Monograph Series, but few if any that covered these related topics in one book in a fashion designed to help the cryogenic engineer and cryophysicist. We hope that the introductory chapter will widen the horizons of many without a solid state background but with a general interest in physics and materials.

The minimum temperature in the natural universe is 2.7 K. Laboratory refrigerators can reach temperatures in the microkelvin range. Modern industrial refrigerators cool foods at 200 K, whereas space mission payloads must be capable of working at temperatures as low as 20 K. Superconducting magnets used for NMR work at 4.2 K. Hence the properties of materials must be accurately known also at cryogenic temperatures. This book provides a guide for engineers, physicists, chemists, technicians who wish to approach the field of low-temperature material properties. The focus is on the thermal properties and a large spectrum of experimental cases is reported. The book presents updated tables of low-temperature data on materials and a thorough bibliography supplements any further research. Key Features include: ° Detailed technical description of experiments ° Description of the newest cryogenic apparatus ° Offers data on cryogenic properties of the latest new materials ° Current reference review

Provides a detailed examination of theory and techniques in thermal expansion of solids. Subjects include a generalized theory, estimation techniques and selected effects, temperature measurements in solids, thermal expansion by X-ray diffraction, high sensitivity expansivity measurement techniques,

This work was begun quite some time ago at the University of Oxford during the tenure of an Overseas Scholarship of the Royal Commission for the Exhibition of 1851 and was completed at Banga lore when the author was being supported by a maintenance allowance from the CSIR Pool for unemployed scientists. It is hoped that significant developments taking place as late as the beginning of 1965 have been incorporated. The initial impetus and inspiration for the work came from Dr. K. Mendelssohn. To him and to Drs. R. W. Hill and N. E. Phillips, who went through the whole of the text, the author is obliged in more ways than one. For permission to use figures and other materials, grateful thanks are tendered to the concerned workers and institutions. The author is not so sanguine as to imagine that all technical and literary flaws have been weeded out. If others come across them, they may be charitably brought to the author's notice as proof that physics has become too vast to be comprehended by a single onlooker. E. S. RAJA GoPAL Department of Physics Indian Institute of Science Bangalore 12, India November 1965 v Contents Introduction ................................................................. .

In everyday life, minute thermally-induced elongations are essentially invisible to the naked eye; but even minute expansions can fatally degrade device processing and performance in – for example – the semiconductor industry. Materials which, astonishingly, contract upon heating offer the great advantage of being able to tune the overall thermal expansion of composite materials or to act as thermal-expansion compensators. The development of these negative thermal expansion materials has advanced rapidly during the past fifteen years, and a wide variety of materials of differing types has now been identified, as well as a number of intriguing mechanisms which help to avoid the apparent inviolable tendency of size to increase with temperature. The present work is the most up-to-date summary of the current range of negative thermal expansion materials and of the associated mechanisms. Negative Thermal Expansion Materials, Thermomiotic Behavior, Thermal Stress-Fracture, Thermal Expansion of Composites, Thin-Film Design, Metamaterials

A quick and easy to use source for qualified thermal properties of metals and alloys. The data tables are arranged by material hierarchy, with summary tables sorted by property value. Values are given for a range of high and low temperatures. Short technical discussions at the beginning of each chapter are designed to refresh the reader's understanding of the properties and units covered in that section