Nanoindentation and in situ microcompression in different dose regimes of proton beam irradiated 304 SS

Abstract

Recent developments in micromechanical testing have allowed for the efficient evaluation of radiation effects in micron-scale volumes of ion-irradiated materials. In this study, both nanoindentation and in situ SEM microcompression testing are carried out on 10 dpa proton beam irradiated 304 stainless steel to assess radiation hardening and radiation-induced deformation mechanisms in the material. Using a focused ion beam (FIB), arrays of 2 μm x 2 μm cross-section microcompression pillars are fabricated in multiple dose regimes within the same grain, providing dose-dependent behavior in a single crystal orientation. Analysis of the microcompression load-displacement data and real-time SEM imaging during testing indicates significant hardening, as well as increased localization of deformation in the irradiated material. Although nanoindentation results suggest that irradiation hardening saturates at low doses, microcompression results indicate that the pillar yield stress continues to rise with dose above 10 dpa in the tested orientation.

Dislocation plasticity in FeCoCrMnNi high-entropy alloy: quantitative insights from in situ transmission electron microscopy deformation

“…(c) Size dependence of the shear stress at 1% engineering strain measured from micropillars. Shear stress from submicron pillars deformed in TEM is plotted together with previously published results of in situ SEM testing with the same bulk material (red squares)[18] and other FCC materials data[19,20,[23][24][25].…”

Hardening and Creep of Ion Irradiated CLAM Steel by Nanoindentation

“…Nanoindentation hardness results shown in Figure 3 and Table 2 demonstrate that ion irradiation can result in the increase of hardness and the magnitude of irradiation hardening increases with the irradiation dose. Many previous studies have been conducted on the irradiation hardening of different materials, including CLAM steel [9,10,[14][15][16][17][18][19][20][21][22]64]. Generally, by neglecting the effects of implanted ions [64], it is attributed to the fact that irradiation-induced defects such as dislocation loops impede the glide of dislocations and can be quantified by the dispersed barrier model [5,19,21]: Since the nanoindentation hardness can be related to yield strength through the Tabor relation [66], one can express the increase of hardness induced by irradiation as:…”

“…Depth-dependent hardness can be directly attained through Continuous Stiffness Measurement [13]. In recent years, a large number of nanoindentation tests have been conducted to investigate the irradiation hardening of metallic materials [9,10,[14][15][16][17][18][19][20][21][22]. Meanwhile, several methods have been developed to obtain nanoindentation creep behavior, including constant rate of loading method [23], constant depth method [24], constant strain rate method [25], constant load method [26], and rate jump method [27].…”

Microstructural examination of neutron, proton and self-ion irradiation damage in a model Fe9Cr alloy

“…The spatial extent of radiation-induced segregation (RIS) at grain boundaries, the hardening, and the defect types and densities were all similar; this proof of principle study has led to a large number of proton irradiation studies. These include studies of radiationinduced interstitial/vacancy defect clusters [17][18][19][20][21][22], precipitation [21][22][23][24][25] and segregation [18,19,22,26], and mechanical changes [15,20,[22][23][24]27]; irradiation assisted stress corrosion cracking has also been studied extensively using proton irradiation [22,28,29]. Studies have also continued to compare proton irradiation to neutron irradiation experiments [17,22].…”