Only the combination of different NDT methods of material characterization is the key to success
Newly developed, as well as „old“ materials have to fulfil requirement profiles for their applications. Material defects, wrong compositions, and wrong material treatment procedures can have severe consequences. Therefore, non-destructive materials testing methods are very important for safety. Nevertheless, for complicated materials problems, several complementary non-destructive methods have to be combined in order to find the right solution. Such methods are described here: By means of the X-ray diffraction (XRD) methods, phase composition, phase transformations, stress states, and textures can be measured. Sometimes, additional statements about the microstructure are achievable as well. Materials composition can be accurately determined by X-ray fluorescence (XRF) and with glow discharge optical emission spectroscopy (GD-OES). Fundamental parameter solution increases the possibilities of the most analytical techniques and is widely used in the X-ray fluorescence analysis and the X-Ray diffraction. Macroscopic and microscopic structures can be derived with computer tomography (CT). In certain cases, even elemental distributions can be observed, e.g. the distributions of lead in brass. To ensure consistent inspection quality the determination of the mechanical material characteristics such as like elasticity module, shear modulus and Poison number is eminent. These parameters should be determined as far as possible non-destructively. Mechanical material properties are important for the assurance of quality, e.g. elasticity properties as the young modulus, the shear modulus, or the Poisson number. They can be derived from ultrasonic (US) measurements. In some cases, even characteristics of the microstructure can be derived in a fast and non-destructive way. With the impulse-echo ultrasonic procedure in diving technology in connection with a special Fourier filtering of the echo signals, these values can also be determined. All the mentioned NDT methods and their beneficial combination are exemplified on brass materials for the judgement about materials faults. In addition, purification procedures and the production of historical objects (brass horse muzzle from 1597) can be derived impressively.