German test centre adds Zwick unit to test fusion reactor materials
22 Nov 2007
Structural materials such as EUROFER 97 for commercial fusion reactors have expected plant lifetimes of about 30 full power years. They must withstand high operational temperatures and coolant pressures as well as high-energy neutrons that can cause hardening, embrittlement and dimensional instability.
The ZHU0.2/Z2.5 has a load range of 2 – 200N, and a displacement measuring resolution of 0.02mm. The system is equipped with a fully automated X/Y table and Rockwell and Vickers indenters. The indentation can be viewed through a microscope fitted with a CCD camera.
The Zwick unit is installed in a gas tight hot cell with 200 mm lead / 500 mm lead glass shielding. It carries out multistage indentation tests with different holding times. Neural networks then evaluate the correlation between these test data and the parameters of a viscoplastic material model, normally acquired from tensile tests.
The operation of the indentation tester is designed for precision loading cycles up to various forces and displacements with predetermined holding times during each cycle. Zwick also supplied materials-testing software to control the machine and obtain the synchronised force and indentation data. Test data is stored in a special format and transmitted to the neural network system to determine the material properties.
