TY - JOUR
T1 - In situ micro tensile testing of He+2 ion irradiated and implanted single crystal nickel film
AU - Reichardt, Ashley
AU - Ionescu, Mihail
AU - Davis, Joel
AU - Edwards, Lyndon
AU - Harrison, R. P.
AU - Hosemann, Peter
AU - Bhattacharyya, Dhriti
PY - 2015/11/1
Y1 - 2015/11/1
N2 - 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 {0 0 1} plane normal was irradiated with 6 MeV 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 [1 0 0] 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 voids or bubbles. 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.
AB - 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 {0 0 1} plane normal was irradiated with 6 MeV 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 [1 0 0] 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 voids or bubbles. 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.
KW - In situ micro-mechanical testing
KW - Ion irradiation
KW - Irradiation hardening
KW - SEM
KW - TEM
UR - http://www.scopus.com/inward/record.url?scp=84941331775&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2015.08.028
DO - 10.1016/j.actamat.2015.08.028
M3 - Article
AN - SCOPUS:84941331775
VL - 100
SP - 147
EP - 154
JO - Acta Materialia
JF - Acta Materialia
SN - 1359-6454
ER -