TMF Testing to ISO 12111 and ASTM E2368

Materials exhibit different behaviors under cyclic thermal loading, similar to cyclic mechanical loading in fatigue. Applications, where materials are subject to high thermal gradients, require additional testing on top of typical static and fatigue tests. These components may be exposed to thermomechanical fatigue (TMF), where they experience cyclic mechanical and thermal loading under service conditions. Contributions of creep and fatigue to the TMF damage in structural integrity under combined thermal and mechanical loading cycles are monitored and analyzed in order to ensure safe operating conditions for the duration of the component’s life cycle.

TMF testing machines help characterize material properties under cyclic mechanical and thermal loading, which contributes to the material selection process for different applications where components are exposed to combined thermal and mechanical loading profiles, including the hot section components in gas turbine generators and jet engines. It also allows engineers to better predict the life cycle of components under these conditions and confirm that computer simulation models correctly predict material behavior under TMF.

TMF applications and research areas include:

• Characterization of materials under combined thermal and mechanical loading cycles
• Effects of different loading phases on materials
• TMF crack initiation in superalloys for gas turbines generators
• TMF life prediction of hot section components in jet engines

Why choose Instron?

Instron Thermomechanical Fatigue (TMF) testing systems provide a fully integrated, turnkey solution for analysis of combined thermal and mechanical loading cycles on high-performance materials. The furnace controller has been updated recently to provide a more intuitive experience, better performance, and more accurate temperature control. Expert integration of proven products has resulted in a complete, user-friendly system perfect for simulating these conditions and measuring material performance.

Benefits

• An external cooling collar is available that offers better performance in cooling rates and minimizing extensometer disturbances
• Multi-coil induction head allows more complex coil designs that optimize the coupling between coils and specimen to improve heating rates and specimen temperature gradients
• Integrated extensometer provides an intuitive strain measurement system that is mounted onto the machine, with minimal setup time and roller mount for quick and precise adjustment of extensometer position
• Precision work head mount for induction coil adjustment, allowing easy and precise movement of the induction system to fit specimen size
• AlignPRO Mechanical alignment fixture is extremely important. As an integrated package with strain gauged specimen and software for measurement of specimen bending, it provides full angularity and concentricity adjustment and instructions to how to adjust, in real time, to give the peace of mind that the load string is properly aligned
• Full system integration with Instron electronics, updated furnace controller package and dedicated TMF Software Package provides an intuitive user experience including testing in compliance with ASTM E2368 and ISO 12111

Alternatively, for more information on Low Cycle Fatigue testing under isothermal conditions, please visit our LCF systems page here.