Small-Scale Mechanical Testing on Proton Beam-Irradiated 304 SS from Room Temperature to Reactor Operation Temperature

Vo, H.T.; Reichardt, Ashley; Howard, C.; Abad, M.D.; Kaoumi, Djamel; Chou, Peter; Hosemann, Peter

doi:10.1007/s11837-015-1596-0

Cited by 22 publications

(3 citation statements)

References 20 publications

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“…Characterizing the irradiation evolution of mechanical properties is challenging, however, because ion irradiation produces a near-surface damage layer on the order of a few hundred nm to a few tens of microns. Logically, small-scale mechanical tests have been utilized on ion irradiated materials, including nanoindentation [1][2][3][4][5][6] and scanning electron microscopic (SEM) in situ pillar compression [7] and cantilever bend tests [1]. However, it remains difficult to isolate the mechanical performance of the ion irradiated layer from that of the unirradiated substrate.…”

Section: Introductionmentioning

confidence: 99%

TEM in situ micropillar compression tests of ion irradiated oxide dispersion strengthened alloy

Yano

Swenson

et al. 2017

Journal of Nuclear Materials

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The growing role of charged particle irradiation in the evaluation of nuclear reactor candidate materials requires the development of novel methods to assess mechanical properties in nearsurface irradiation damage layers just a few micrometers thick. In situ transmission electron microscopic (TEM) mechanical testing is one such promising method. In this work, microcompression pillars are fabricated from a Fe 2+ ion irradiated bulk specimen of a model Fe-9%Cr oxide dispersion strengthened (ODS) alloy. Yield strengths measured directly from TEM in situ compression tests are within expected values, and are consistent with predictions based on the irradiated microstructure. Measured elastic modulus values, once adjusted for the amount of deformation and deflection in the base material, are also within the expected range. A pillar size effect is only observed in samples with minimum dimension ≤ 100 nm due to the low interobstacle spacing in the as received and irradiated material. TEM in situ micropillar compression tests hold great promise for quantitatively determining mechanical properties of shallow ionirradiated layers.

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Section: Introductionmentioning

confidence: 99%

TEM in situ micropillar compression tests of ion irradiated oxide dispersion strengthened alloy

Yano

Swenson

et al. 2017

Journal of Nuclear Materials

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“…The pillars fabricated on B2 and L1 2 phases had different orientation and yield strength changes with grain orientation. Therefore, the critical resolved shear stress (CRSS) was calculated for each phase using Schmid factor [41][42][43] to account for the crystal orientation. The slip system with maximum Schmid factor for B2 phase was (121) [11 1] and for L1 2 phase were two, namely (111)[01 1] and (11 1)[011].…”

Section: Small-scale Mechanical Behavior By Nano-indentationmentioning

confidence: 99%

Small-scale mechanical behavior of a eutectic high entropy alloy

Muskeri

Hasannaeimi

Salloom

et al. 2020

Sci Rep

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eutectic high entropy alloys, with lamellar arrangement of solid solution phases, represent a new paradigm for simultaneously achieving high strength and ductility, thereby circumventing this wellknown trade-off in conventional alloys. However, dynamic strengthening mechanisms and phaseboundary interactions during external loading remain unclear for these eutectic systems. In this study, small-scale mechanical behavior was evaluated for Alcocrfeni 2.1 eutectic high entropy alloy, consisting of a lamellar arrangement of L1 2 and B2 solid-solution phases. The ultimate tensile strength was 1165 MPa with ductility of ~18% and ultimate compressive strength was 1863 MPa with a total compressive fracture strain of ~34%. Dual mode fracture was observed with ductile failure for L1 2 phase and brittle mode for B2 phase. Phase-specific mechanical tests using nano-indentation and micro-pillar compression showed higher hardness and strength and larger strain rate sensitivity for B2 compared with L1 2. Micro-pillars on B2 phase deformed by plastic barreling while L1 2 micro-pillars showed high density of slip steps due to activation of more slip systems and homogenous plastic flow. Mixed micropillars containing both the phases exhibited dual yielding behavior while the interface between L1 2 and B2 was well preserved without any sign of separation or cracking. Phase-specific friction analysis revealed higher coefficient of friction for B2 compared to L1 2. These results will pave the way for fundamental understanding of phase-specific contribution to bulk mechanical response of concentrated alloys and help in designing structural materials with high fracture toughness. Multi-principal element alloys (MPEAs), also known as high entropy alloys (HEAs), offer a new paradigm in structural alloy design and development owing to their appealing physical and mechanical properties such as high fracture toughness, good wear and fatigue resistance, high strength and good elevated temperature properties 1-3. Several HEA systems have been reported with a single-phase face center cubic (FCC) or body center cubic (BCC) structure 4-6. To concurrently achieve good ductility of FCC HEAs along with high strength of BCC HEAs, eutectic high entropy alloys (EHEAs) have recently been developed to overcome the limitations of single-phase HEAs 7. EHEAs typically consist of a mixture of two solid-solution phases in the form of lamellae or rod-like dispersions in a matrix. To date, several EHEAs have been reported with excellent combination of high strength and ductility including CoFeNi 1.

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“…the minimum dimension and the obstacle spacing on the glide plane [45]. [66], and cantilever bend tests [40]. However, it remains difficult to isolate the mechanical performance of the ion irradiated layer from that of the unirradiated substrate.…”

Section: Ods Size Effect Factorsmentioning

confidence: 99%

In Situ TEM Micropillar Compression Testing in Irradiated Oxide Dispersion Strengthened Alloys

Yano¹

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To start, I would like to thank my advisor, Dr. Janelle Wharry, for her patience and endless support throughout this effort. Thank you especially to Dr. Claire Xiong for being willing to oversee my last year here at BSU and for the push to complete this thesis. I'd also like to acknowledge and thank my other committee members for their participation in this process. Much of this work was conducted at the MaCS at CAES. Jatu Burns and Allyssa Bateman-thanks for sharing your wisdom and knowledge of the FIB. Joanna Taylorthanks for accommodating my last-minute schedule changes. Dr. Yaqiao Wu-thank you for all your help on the TEM. Without your assistance loading my samples into the Picoindenter, I'm afraid many more samples would have been lost. Your expertise with the TEM was essential and saved me many grueling hours aligning the indenter tip. Matthew Swenson-thanks for all your help in this endeavor. I appreciate all the time you took to teach me the ropes, all the long drives to Idaho Falls, and all the latenights FIB-ing out samples. Your mentorship gave me a jump-start onto this whole graduate school process and I will always be grateful for your wise words and perspective.

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Small-Scale Mechanical Testing on Proton Beam-Irradiated 304 SS from Room Temperature to Reactor Operation Temperature

Cited by 22 publications

References 20 publications

TEM in situ micropillar compression tests of ion irradiated oxide dispersion strengthened alloy

TEM in situ micropillar compression tests of ion irradiated oxide dispersion strengthened alloy

Small-scale mechanical behavior of a eutectic high entropy alloy

In Situ TEM Micropillar Compression Testing in Irradiated Oxide Dispersion Strengthened Alloys

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