The Effects of Grain Size and Texture on Dynamic Abnormal Grain Growth in Mo

Noell, Philip; Taleff, Eric M.

doi:10.1007/s11661-016-3644-y

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…In general, the circumstances under which AGG occurs are manifold 1,48 ; however, the phenomenon has usually been investigated under static annealing conditions 49–54 . In the past decade AGG was observed during high-temperature plastic deformation of molybdenum and tantalum 46,48,55–57 . It was shown that AGG under these dynamic conditions leads to very large abnormal grains 46,48,58 .…”

Section: Introductionmentioning

confidence: 99%

Promoting abnormal grain growth in Fe-based shape memory alloys through compositional adjustments

et al. 2019

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Iron-based shape memory alloys are promising candidates for large-scale structural applications due to their cost efficiency and the possibility of using conventional processing routes from the steel industry. However, recently developed alloy systems like Fe–Mn–Al–Ni suffer from low recoverability if the grains do not completely cover the sample cross-section. To overcome this issue, here we show that small amounts of titanium added to Fe–Mn–Al–Ni significantly enhance abnormal grain growth due to a considerable refinement of the subgrain sizes, whereas small amounts of chromium lead to a strong inhibition of abnormal grain growth. By tailoring and promoting abnormal grain growth it is possible to obtain very large single crystalline bars. We expect that the findings of the present study regarding the elementary mechanisms of abnormal grain growth and the role of chemical composition can be applied to tailor other alloy systems with similar microstructural features.

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Section: Introductionmentioning

confidence: 99%

Promoting abnormal grain growth in Fe-based shape memory alloys through compositional adjustments

et al. 2019

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“…Okayasu, Fukutomi and coworkers investigated dynamic grain growth in Al-Mg and Al-Cu binary solid-solution alloys [13,14] and in Fe-3 pct Si. [15] Another is recent work on dynamic abnormal grain growth in the BCC refractory metals Mo [16,[18][19][20][21][22] and Ta. [17] Investigations of superplasticity are particularly interested in dynamic grain growth because the grain boundary-sliding deformation mechanism responsible for the majority of superplastic behavior is very sensitive to grain size.…”

Section: B Dynamic Grain Growthmentioning

confidence: 99%

“…However, the literature does contain information from a number of studies concerned with dynamic normal grain growth [9][10][11][12][13][14][15] and dynamic abnormal grain growth. [16][17][18][19][20][21][22] This study investigates the nature of grain growth in an IF steel for both static and dynamic conditions.…”

Section: Introductionmentioning

confidence: 99%

Creep Deformation and Dynamic Grain Growth in an Interstitial-Free Steel

Rupp

Noell

Taleff

2020

Metall Mater Trans A

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Dynamic grain growth is demonstrated to be much faster than static grain growth in a body-centered-cubic, interstitial-free steel sheet material at 850 C. Dynamic grain growth occurs during concurrent plastic deformation at elevated temperature, whereas static grain growth occurs during static annealing. Grain growth during steady-state plastic flow in tension at 850 C to a true strain of 0.2 at a true-strain rate of 10 À4 s À1 doubled grain size, while static annealing for the same time produced no increase in grain size. This is described as dynamic normal grain growth (DNGG) because no abnormally large grains were observed. The recrystallized microstructure of the steel demonstrated a log-normal distribution of grain sizes. DNGG produced bimodal grain size distributions that deviate from the theoretical expectation of a simple shift to larger sizes during normal growth. The bimodal distributions contained a remnant of small grains that were not consumed during grain growth. DNGG produced a crystallographic texture that is unique from both the recrystallized material and that produced by lattice rotation alone. DNGG strengthened the f111gh110i and f111gh112i components of the strong c-fiber component in the original recrystallization texture. Lattice rotation from tensile deformation, by contrast, strengthened the a-fiber components that intersect the original c-fiber.

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“…In extreme cases, abnormal grains can consume the entire microstructure to produce a uniformly coarse grain size or even a single crystal [2][3][4][5][6][7]. AGG is thus of interest for producing single crystals in the solid state, a capability demonstrated in the laboratory for molybdenum (Mo) [8][9][10][11][12][13][14] and tantalum (Ta) [15]. For grain-oriented silicon steels, AGG is desired and necessary to produce the coarse, highly-textured microstructures required for optimal performance in electrical transformers [16].…”

Section: Introductionmentioning

confidence: 99%

“…Prior investigations demonstrated the importance of grain-boundary curvature and concurrent plastic deformation in the growth of abnormal grains by DAGG [10][11][12][13][14][15]. Grain-boundary curvature was demonstrated to supply the most important driving force for DAGG in Mo, and concurrent deformation is thought to primarily increase boundary mobility during DAGG [11][12][13]. However, the critical strains required for DAGG initiation indicate that significant dislocation substructure likely forms within the interiors of deformed grains prior to DAGG [25].…”

Section: Introductionmentioning

confidence: 99%

Growth of preexisting abnormal grains in molybdenum under static and dynamic conditions

Noell

Worthington

Taleff

2017

Materials Science and Engineering: A

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This investigation compares the growth rates of preexisting abnormal grains under both static and dynamic conditions. Abnormal grains several millimeters in length were produced in two commercial-purity molybdenum (Mo) materials by tensile straining at temperatures from 1923 to 2073 K (1650 to 1800 • C). This process is termed dynamic abnormal grain growth (DAGG) because it produces abnormal grains during concurrent plastic straining. DAGG creates abnormal grains at much lower temperatures than does static abnormal grain growth (SAGG). Abnormal grains created through DAGG were characterized with their surrounding microstructures and were then subjected to annealing treatments. Only one-third of the preexisting abnormal grains subsequently grew by SAGG. Among these, SAGG occurred only in those specimens that required the largest strains to initiate DAGG when creating the abnormal grain(s). The rates of boundary migration observed for SAGG were approximately two orders of magnitude slower than those for DAGG. When DAGG in one specimen was interrupted by extended static annealing, it did not recur when straining resumed. The dislocation substructure developed during hot deformation, which includes subgrains typical of five-power creep, is critically important to both DAGG and SAGG of preexisting abnormal grains under the conditions examined.

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The Effects of Grain Size and Texture on Dynamic Abnormal Grain Growth in Mo

Cited by 15 publications

References 27 publications

Promoting abnormal grain growth in Fe-based shape memory alloys through compositional adjustments

Promoting abnormal grain growth in Fe-based shape memory alloys through compositional adjustments

Creep Deformation and Dynamic Grain Growth in an Interstitial-Free Steel

Growth of preexisting abnormal grains in molybdenum under static and dynamic conditions

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