• Sintered silicon nitride sample

    Sintered silicon nitride is the leading ceramic for high load structural applications. The internal friction behavior can give information about the crystal structure together with the fatigue resistance. 2 internal friction peaks can be observed.
    - P1: Si3N4 contains a secondary, intergranular phase. This phase is (partially) amorphous, and softens above its glass transition temperature (typically near 1000°C). This triggers viscous deformation of the bulk ceramic and consequently increases the internal friction. For cyclically loaded components operating near this peak, this energy dissipation constitutes an effective increase in fracture resistance.
    - P2: Around 1300°C, a local increase in the resonant frequency can be observed which points to stiffening of the material. This stiffening is typically the consequence of crystallization which indicates that the second internal friction peak is caused by the crystallization of the amorphous intergranular phase. During cooling, when the crystallization is completed, the peak doesn’t return.

    Measured with RFDA HTVP1600 , Measured with RFDA HT1600
  • High alumina castable material

    The obtained elastic properties at elevated temperatures give a detailed insight into the extend of material bonding and its behavior under stress and rude conditions around 1600°C. The Young’s modulus curve decrease significantly at around 300°C which is characteristic of the dehydration of the cement in the concrete. After 800°C, the Young’s modulus increase up to the maximum temperature which indicates a sintering process in the material. The damping phenomena are high at about 880°C and 1284°C characterizing the imperfection that occur during the crystallization of cement component and fine element in the castable refractory material. After heating and subsequent cooling, the final Young’s modulus was around 38 GPa.
    Measured with RFDA HT1700 , Measured with RFDA HTVP1700C
  • Refractory materials

    Refractory materials must be chemically and physically stable at high temperatures. Especially for these porous materials, the impulse excitation technique can be successfully applied due to the small mechanical forces avoiding internal material deformations. The refractory sample is measured starting from the green stage up to 1550°C at 3 °C/min, stayed at 1550 °C for 30 minutes and cooled down at 3 °C/min. Measurements were taken every 2 minutes. The different phase transformations are clearly observed during the heating and cooling phase. Furthermore, the technique can also be used to study the thermal shock behavior of refractory materials.
    Measured with RFDA HTVP1600 , Measured with RFDA HT1600
  • Aluminum sample

    IET measurements are performed in predefined intervals during heating and cooling (1-5 °C/min) in order to determine the elastic properties as function of the temperature. In this case, the Young's modulus and shear modulus of an aluminum sample are determined up to 260°C.
    Measured with RFDA HT650
  • High-carbon steel C68

    High-carbon steels are used for applications in which high strength, hardness and wear resistance are necessary. In this case, the high-carbon steel C68 shows a monotonic decrease in Young's modulus with increasing temperature between room temperature and 600°C. The Young's modulus decreases from 216.46 GPa at room temperature to 125.9 GPa at 800°C. After 700°C, a phase transition can explain the variable decrease of the Young's modulus. The reliability and accuracy of material data leads to clear advantages in structural design calculations and modelling, for example, finite element analysis of stresses in high temperature plant components.
    Measured with RFDA HT650