Nanoindentation and TEM Characterization of Ion Irridiated 316L Stainless Steels

Hattar, Khalid Mikhiel; Buchheit, Thomas Edward; Kotula, Paul Gabriel; McGinnis, A.L.; Brewer, Luke N.

doi:10.1002/9781118365038.ch43

Cited by 2 publications

(1 citation statement)

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“…One of the drawbacks of using this method is that the damaged region is very shallow (generally <20 µm), and mechanical testing of such thin layers is extremely difficult. This problem has been solved partially by using nanoindentation to probe the hardness changes of such thin irradiated materials [6][7][8][9][10]. However, the results of nanoindentation tests are difficult to interpret due to two reasons: (a) it is a test with a tri-axial stress state, hence deriving uniaxial tensile properties out of such tests is difficult, and (b) since the process creates a 3-dimensional plastic zone around it that grows with the depth of the indent in a manner which is material dependent, the hardness values measured by nanoindentation are an average of a somewhat uncertain volume of material around the indent [11,12].…”

Section: Introductionmentioning

confidence: 99%

In situ micro tensile testing of He+2 ion irradiated and implanted single crystal nickel film

et al. 2015

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The effect of ion irradiation on the tensile properties of pure Ni single crystals was investigated using an in situ micro-mechanical testing device inside a scanning electron microscope. A 12.8 µm-thick Ni film with {001} plane normal was irradiated with 6MeV He +2 ions to peak damage of 10 and 19 displacements per atom (dpa). Micro-tensile samples were fabricated from the specimens parallel to the plane of the film using a focused ion beam (FIB) instrument, and tested in tension along [100] direction, up to fracture. The peak strength increased from ~230 MPa for the unirradiated material to about 370 MPa and 500 MPa for the 10 dpa and 19 dpa samples respectively, while the ductility decreased with increasing dose. The surface near the peak damage regions fractured in a brittle manner, while the regions with smaller dose underwent significant plastic deformation. Slip bands extended to the peak-damage zone in the sample with a dose of 19 dpa, but did not propagate further. Transmission electron microscopy confirmed the stopping of the slip bands at the peak-damage region, just before the high He concentration region with cavities. By removing the peak damage region and the He bubble region with FIB, it was possible to attain propagation of slip bands through the entire remaining thickness of the sample. This material removal also made it possible to calculate the irradiation hardening in the region with peak hardness-thus enabling the separation of hardening effects in the high and low damage regions.

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