Accelerated precipitation in the AFA stainless steel Fe–20Cr–30Ni–2Nb–5Al via cold working

Post-dynamic recrystallization and γ' precipitation during cooling from γ' supersolvus temperature after hot compression have been studied in the AD730 TM γ-γ' Nickel-based superalloy. Emphasis was given not only on both phenomena as distinct mechanisms but also on their mutual influence in terms of physical mechanisms. The growth of γ'precipitates is hastened in the unrecrystallized grains compared to the recrystallized ones.This could possibly be attributed to the higher dislocation content acting as highdiffusivity paths. Post-dynamic recrystallization is not prevented by Smith-Zener pinning of the recrystallization front by the γ' precipitates. Instead, the recrystallization front dissolves γ' precipitates which then reprecipitate discontinuously or continuously, and coherently with the surrounding γ matrix in the recrystallized grains.

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“…For example, dislocations can promote precipitation in many alloys [17,18] including Ni-based superalloys [19,20].…”

Section: Introductionmentioning

confidence: 99%

On the Coupling between Recrystallization and Precipitation Following Hot Deformation in a γ-γ′ Nickel-Based Superalloy

Seret

Moussa

Bernacki

et al. 2018

Metall Mater Trans A

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“…Basically, the strengthening of steels involves the controlled creation of internal obstacles to impede the motion of dislocations [1]. Uniform precipitation of nanoparticles has been recognized as one of the most effective methods to increase the tensile and/or creep strength of steels [2][3][4][5][6][7]. The degree of strengthening so obtained is highly dependent upon the type, number density, size and spatial distribution of the particles, and also the nature of the interaction of the dislocations with the particles [1].…”

Section: Introductionmentioning

confidence: 99%

Precipitation mechanism and mechanical properties of an ultra-high strength steel hardened by nanoscale NiAl and Cu particles

et al. 2015

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a b s t r a c tWe report on the alloy design strategies, precipitation mechanism and mechanical properties of an ultra-high strength steel hardened by co-precipitation of nanoscale NiAl and Cu particles. The steel, developed through a computational-aided alloy design approach, exhibits a tensile strength of $1.9 GPa, an elongation of $10% and a reduction in area of $40%. Atom probe tomography (APT) reveals an interesting type of co-precipitation mechanism of NiAl and Cu nanoparticles, in which the NiAl particles first come out of the supersaturated solid solution and the rejection of Cu solutes leads to the heterogeneous precipitation of Cu particles adjacent to the NiAl particles. The observed precipitation sequence of ''supersaturated solid solution ? NiAl ? NiAl + Cu'' is substantially different from the one previously reported in Cu-strengthened steels, which involves the process of ''supersaturated solid solution ? Cu ? Cu + NiAl''. The modulation of the precipitation sequence is attributed not only to the relatively high Ni/Cu and Al/Cu ratios but also the synergistic combination of Ni, Al, Mn and Cu additions in the steel. In addition, APT also reveals the precipitation of a small amount of nanoscale Fe 3 (Mo, W) 3 Cand NbC-type carbides. The combination of the strengthening effects from the nanoscale NiAl particles, Cu particles and carbides contributes significantly to the overall ultra-high strength of the steel.

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“…The as-cast alloy was homogenized in argon for 24 h at 1250 1C and water quenched. This homogenization treatment produces a single phase material [19]. Samples were subsequently aged in air for 2.4 h, 24 h, 240 h, 480 h and 1325 h at 800 1C.…”

Section: Methodsmentioning

confidence: 99%

“…Samples were prepared for SEM analysis by polishing with successively finer grits of silicon carbide paper, up to 1200 and with 0.3 and 0.05 mm alumina powder in a water to obtain a mirror finish. Backscattered electron (BSE) images from the specimens were processed using ImageJ [20] using a routine described in a previous paper [19] that uses Z-contrast to distinguish precipitates.…”

Section: Methodsmentioning

confidence: 99%

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The effect of aging on the microstructure and mechanical behavior of the alumina-forming austenitic stainless steel Fe–20Cr–30Ni–2Nb–5Al

Trotter

Baker

2015

Materials Science and Engineering: A

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Accelerated precipitation in the AFA stainless steel Fe–20Cr–30Ni–2Nb–5Al via cold working

Cited by 60 publications

References 25 publications

On the Coupling between Recrystallization and Precipitation Following Hot Deformation in a γ-γ′ Nickel-Based Superalloy

On the Coupling between Recrystallization and Precipitation Following Hot Deformation in a γ-γ′ Nickel-Based Superalloy

Precipitation mechanism and mechanical properties of an ultra-high strength steel hardened by nanoscale NiAl and Cu particles

The effect of aging on the microstructure and mechanical behavior of the alumina-forming austenitic stainless steel Fe–20Cr–30Ni–2Nb–5Al

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