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Creep and Fatigue Testing at High Temperature

Increases in performance in high-performance applications can often only be achieved through increased thermal and mechanical loads on the components. However, in the case of many materials this requirements specification leads to failure (through creep and/or fatigue). For example, many metals exhibit structural changes under load, starting at 30 to 40% of their melting temperature, which lead to irreversible plastic deformation. The Kappa creep test machines from ZwickRoell are optimally suited to determine the maximum service life of components under this type of load.

Based on the patented Kappa 100 SS-CF creep test machine, ZwickRoell now also provides a precisely controlled test solution, with which thermo-mechanical material fatigue can be simulated. The material is inductively heated, the hydraulic grips and the HT extensometer are water cooled for protection from the high temperatures. A TMF controller synchronizes mechanical and thermal loading. As an alternative system combination, the Kappa 100 SS-CF is used with a 3-zone furnace for temperatures up to 1,200 °C. With these testing systems, material fatigue and crack growth are simulated through variable cyclic loads. A contact-type HT extensometer, which is also water-cooled, is used to record deformation. The test programs for creep-fatigue test, such as creep crack growth (CCG), low-cycle fatigue (LCF), creep-fatigue (CF), fatigue crack growth rates (FCGR) and creep-fatigue crack growth (CFGR) are included in testXpert R.

For creep tensile tests in air up to 1,500 °C, systems are available based on the Kappa 50 SS creep test machine. They are equipped with a 3-zone high temperature furnace and a ceramic load string up to 1,500 °C for round and flat specimens. With the laserXtens HP/TZ non-contact extensometer measurements can be performed up to break, without influence on the specimen and without damaging the extensometer.

At a glance:

  • The Kappa series from ZwickRoell provides high precision and highly versatile creep test machines
  • Thermo-mechanical fatigue testing with induction heating and air cooling
  • Creep tests in air up to 1,500 °C with ceramic load string and non-contact laserXtens extensometer
  • Simulation of material fatigue or crack growth up to 1,200 °C