Fusion Programme - ENEA - Fusione

3. Technology Programme2007 Progress Reportuse of Li 2 CO 3 pellets enriched in 6 Li up to 90% was also considered in order to increase the sensitivity ofthe technique (fig. 3.37). Measurements of the tritium production rate will be performed also with the useof other independent techniques, i.e., TLD detectors and 6 Li-covered diamond detectors. All themeasurements have been detailed.Construction of the neutronics HCLL mockup could not be started as planned (for October 2007) becausethe LiPb material was not delivered by the firm producing it for EFDA (EFDA contract).3.7 MaterialsIndentationcreep testingIn collaboration with theUniversity of Rome TorVergata ENEA hasd e v e l o p e dinstrumentation andmathematical models for performing andinterpreting cylindrical-indentation tests. In2007 a special mechanical apparatus,consisting of two levers of the second kindin series (fig. 3.38), was produced toperform creep tests with a cylindricalindenter. Creep tests constitute a way toanalyse the resistance of the structures ofmaterials that have to operate at hightemperature. Deformation at constantload and temperature is tested by directlysubmitting a viscoelastic specimen to theload and measuring its deformation as afunction of time.Compared to conventional creepexperiments, indentation creep tests haveseveral advantages. For example, onlysmall amounts of materials are neededand sample preparation is simple. Somenumerical and experimental research hasbeen performed to build the relationshipbetween indentation creep testing andconventional uniaxial creep testing.The creep tests were performed with a1–mm-diam cylindrical indenter on F82Hferritic martensitic steel at a temperature of535°C (fig. 3.39) and on the AA2014.8aluminium alloy at 150°C. Figure 3.40reports comparisons between dataobtained by conventional uniaxial creeptesting and data from indentation creeptesting for the F82H.Indentation depth (μm)40302010Fig. 3.38 - Indentation creep testerForce applied on the indenter 660 NForce applied on the indenter 705 NForce applied on the indenter 750 NTemperature = 535°C00 20000 40000 60000 80000Time (s)Fig. 3.39 - Indentation creep depth as a function of creep time63