High precision measurements on metallic systems using Fast Scanning Calorimetry

Cameron Quick

Research output: ThesisDoctoral Thesis

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Abstract

Modern metallurgy and alloy design can make use of a multitude of characterisation techniques to develop materials and processes for desirable properties such as low density and high strength. However, the technical capabilities of modern devices are in some cases ahead of the practical expertise, and state of the art research can greatly benefit from an optimised and robust execution of experiments. This thesis explores some approaches to high precision measurements on metallic systems using micro electromechanical systems-based (MEMS-based) technologies, with a particular focus on Fast Differential Scanning Calorimetry (FDSC). FDSC uses modern MEMS fabrication techniques in the construction of a nanocalorimeter which achieves high sensitivity and heating rates orders of magnitude faster than conventional calorimetry devices. Material heat capacity was investigated, owing firstly to its well documented and calculable equilibrium properties, and secondly to its practical importance for materials science. Precise heat capacity measurements were made on pure lead and aluminium, where comparisons to literature helped develop and validate an experimental methodology based on cyclic thermal treatments and a correction for intrinsic heat losses. A eutectic AlSi12 alloy is then similarly examined at rapid heating rates comparable to those occurring during metal additive manufacturing. Varied quench and re-heating rates reveal the kinetics of the supersaturated Al-Si system, while the experimental approach is carefully explained to inform related experiments using FDSC. A further MEMS-based technique was also explored, whereby sample heating in-situ inside a transmission electron microscope (TEM) is possible. Novel sample preparation techniques were employed, similar to those used for metallic foil preparation in FDSC, to investigate heat treatment in an AlMgZn(Cu) aluminium crossover alloy. The specific approach to sample preparation is described in detail and its merits are discussed in comparison to more conventional methods, while the techniques and results are demonstrative for related experiments on metallic foils.
Translated title of the contributionHochpräzise Messungen an metallischen Systemen mit Fast-Scanning-Kalorimetrie
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Kozeschnik, Ernst, Assessor A (external), External person
  • Antrekowitsch, Helmut, Co-Supervisor (internal)
  • Uggowitzer, Peter, Assessor A (internal)
  • Pogatscher, Stefan, Supervisor (internal)
DOIs
Publication statusPublished - 2023

Bibliographical note

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Keywords

  • Calorimetry
  • Aluminium alloy
  • Micro-electromechanical systems (MEMS)
  • Specific heat capacity
  • Transmission electron microscopy (TEM)

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