Doctoral Dissertations

Abstract

"Thermal lattice expansion studies of various types of solids were carried out in this investigation and were corelated to their crystallographic and various other properties. The advantages and limitations of various methods of studying thermal expansion are discussed in detail. A new design for a versatile low temperature camera to study expansion by an X-ray method is proposed. The thermal lattice expansion of silicon was negative below 119ºK. This behavior is discussed in terms of crystal structure and interatomic bonding. Diamond exhibits no anomalous thermal expansion. Lattice parameter data for many metals at low temperatures are reported for the first time. The thermal expansion behavior of Fe, Cu, Ni, W and Cr is typical for metals. A large difference between the present results and the published data (obtained by measuring bulk expansion) was observed for tungsten. This is explained in terms of the lack of a theoretical density for the bulk samples. Tungsten and chromium show no thermal expansion anomalies despite the theoretical predictions and some indirect evidence. The small magnitude of the thermal expansion of Al₂Au is discussed in terms of the interatomic bonding in the structure. LiF shows constant values of Gruneisen parameters at unusually high temperatures. The thermal expansion behavior of magnetic intermetallic compounds such as R₂M₁₇, (R=Y,Lu,Gd and M=Fe,Co,Ni) is clearly corelated to their magnetic properties and crystallographic structures. An anomalous thermal expansion in the c̲ direction is found for R₂Fe₁₇ compounds below their magnetic ordering temperatures. This is explained in terms of the Fe-Fe interatomic distances and number of Fe nearest neighbors in the crystal. No such anomalous behavior is found for the isostructural R₂sCo₁₇, or R₂sNi₁₇ compounds. The ferromagnetic to helimagnetic transition in Lu₂Fe₁₇ can be understood as due to negative direct interact ions and stored magnetic energy in the substitution zone"--Abstract, pages ii-iii.

Advisor(s)

Straumanis, Martin E., 1898-1973

Committee Member(s)

James, William Joseph
Clark, J. B. (J. Beverley)
Frad, William A.
Suzuki, Tetsuro

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Sponsor(s)

Air Force Materials Laboratory (U.S.)
University of Missouri--Rolla

Publisher

University of Missouri--Rolla

Publication Date

1971

Pagination

xii, 114 pages

Note about bibliography

Includes bibliographical references (pages 110-113).

Rights

© 1971 Jayantkumar Shantilal Shah, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Solutions, Solid -- Effect of heat onMetals -- Heat treatmentExpansion (Heat) -- MeasurementCrystal latticesIntermetallic compounds -- Thermal properties

Thesis Number

T 2422

Print OCLC #

6024445

Electronic OCLC #

858681811

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Metallurgy Commons

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