Metallurgists employ a number of experimental methods not normally encountered by the solid state physicist. Several of these will be described and critically assessed in the following chapter because the data they can provide will be drawn upon in subsequent chapters. Naturally many experimental techniques are standard for both solid state physicists and metallurgists, for example X-ray methods for the determination of crystal structure, lattice parameters and crystallographic orientation [2.1], [2.2], based on the Bragg relationship for constructive interference of X-rays scattered by the atoms in the lattice. Similarly, both physicists, and metallurgists make use of measurements of electrical conductivity, Hall voltage, macroscopic density and its variation with temperature (thermal expansion), although the metallurgist usually measures the latter uni-dimensionally in a dilatometer. Nor do measurements of elastic moduli, specific heat or magnetic susceptibility introduce the physicist to any new methods. Results of these and related investigations will be referred to without any detailed description of the procedure. Relevant techniques are summarized in [2.3], [2.4], [2.5].
Microscopy of surfaces
Apart from their crystal structure, metals possess a microstructure, in that they consist of differently oriented grains or differently constituted phases. The observation and if possible quantitative description of this microstructure is the aim of metallography, which employs optical, electron, ion and X-ray microscopical methods, some of which are described in sections 2.2 and 2.4.