Amorphous complexions enable a new region of high temperature stability in nanocrystalline Ni-W

Schuler, Jennifer D.; Donaldson, Olivia K.; Rupert, Timothy J.

doi:10.1016/j.scriptamat.2018.05.023

Cited by 53 publications

(26 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This finding is in agreement with previously reported results from a study of a binary Cu-Zr alloy [28,29]. The formation of AIFs has also been achieved in a variety of other metallic alloy systems, such as Mo-Ni [26], Ni-W [52], and Cu-Hf [32], with no abnormal grain growth reported.…”

Section: Microstructural Evolution During Annealingsupporting

confidence: 92%

Thick amorphous complexion formation and extreme thermal stability in ternary nanocrystalline Cu-Zr-Hf alloys

Grigorian

Rupert

2019

Acta Materialia

Self Cite

View full text Add to dashboard Cite

Building on the recent discovery of tough nanocrystalline Cu-Zr alloys with amorphous intergranular films, this paper investigates ternary nanocrystalline Cu-Zr-Hf alloys with a focus on understanding how alloy composition affects the formation of disordered complexions. Binary Cu-Zr and Cu-Hf alloys with similar initial grain sizes were also fabricated for comparison. The thermal stability of the nanocrystalline alloys was evaluated by annealing at 950 °C (>95% of the solidus temperatures), followed by detailed characterization of the grain boundary structure. All of the ternary alloys exhibited exceptional thermal stability comparable to that of the binary Cu-Zr alloy, and remained nanocrystalline even after two weeks of annealing at this extremely high temperature. Despite carbide formation and growth in these alloys during milling and annealing, the thermal stability of the ternary alloys is mainly attributed to the formation of thick amorphous intergranular films at high temperatures. Our results show that ternary alloy compositions have thicker boundary films compared to the binary alloys with similar global dopant concentrations.While it is not required for amorphous complexion formation, this work shows that having at least three elements present at the interface can lead to thicker grain boundary films, which is expected to maximize the previously reported toughening effect.

show abstract

Section: Microstructural Evolution During Annealingsupporting

confidence: 92%

Thick amorphous complexion formation and extreme thermal stability in ternary nanocrystalline Cu-Zr-Hf alloys

Grigorian

Rupert

2019

Acta Materialia

Self Cite

View full text Add to dashboard Cite

show abstract

“…11,12 This potential lack of thermal stability, even at room temperature, 5,6 can lead to a degradation of strength over time. To address these limitations, there are several methods to improve thermal and/or mechanical properties, including the use of grain boundary engineered nanocrystalline metals such as nanotwinned metals, [13][14][15] the use of a bimodal grain structures, [16][17][18] the incorporation of amorphous grain boundaries in the material, [19][20][21] orof specific interest to this study the use alloyed nanocrystalline metals that display solute segregation. [22][23][24][25] Other studies have examined the role of alloy-ing on solute drag and Zener pinning, as well as grain boundary segregation, grain refinement, and thermodynamic stabilization.…”

Section: Introductionmentioning

confidence: 99%

New nanoscale toughening mechanisms mitigate embrittlement in binary nanocrystalline alloys

et al. 2018

View full text Add to dashboard Cite

show abstract

“…AIFs strongly resist grain growth, so much that even when nanocrystalline ball milled Cu-Zr containing AIFs was held at 98% of its solidus temperature for a week, it remained nanocrystalline [23]. In fact, Schuler et al [35] even observed a new regime of high temperature nanocrystalline stability due to AIF formation in Ni-W alloys. The ability of AIFs to both stabilize the grain size and diffuse local grain boundary strain concentrations may contribute to the absence of grain coarsening in the AIF-containing sample at fatigue crack nucleation.…”

Section: Resultsmentioning

confidence: 99%

In Situ High-Cycle Fatigue Reveals Importance of Grain Boundary Structure in Nanocrystalline Cu-Zr

Schuler¹,

Barr²,

Heckman³

et al. 2019

JOM

Self Cite

View full text Add to dashboard Cite

Nanocrystalline metals typically have high fatigue strengths, but low resistance to crack propagation. Amorphous intergranular films are disordered grain boundary complexions that have been shown to delay crack nucleation and slow crack propagation during monotonic loading by diffusing grain boundary strain concentrations, suggesting they may also be beneficial for fatigue properties. To probe this hypothesis, in situ transmission electron microscopy fatigue cycling is performed on Cu-1 at.% Zr thin films thermally treated to have either only ordered grain boundaries or to contain amorphous intergranular films. The sample with only ordered grain boundaries experienced grain coarsening at crack initiation followed by unsteady crack propagation and extensive nanocracking, whereas the sample containing amorphous intergranular films had no grain coarsening at crack initiation followed by steady crack propagation and distributed plastic activity. Microstructural design for control of these behaviors through simple thermal treatments can allow for the improvement of nanocrystalline metal fatigue toughness.

show abstract

Amorphous complexions enable a new region of high temperature stability in nanocrystalline Ni-W

Cited by 53 publications

References 58 publications

Thick amorphous complexion formation and extreme thermal stability in ternary nanocrystalline Cu-Zr-Hf alloys

Thick amorphous complexion formation and extreme thermal stability in ternary nanocrystalline Cu-Zr-Hf alloys

New nanoscale toughening mechanisms mitigate embrittlement in binary nanocrystalline alloys

In Situ High-Cycle Fatigue Reveals Importance of Grain Boundary Structure in Nanocrystalline Cu-Zr

Contact Info

Product

Resources

About