Study of influence of gamma prime and eta phases on corrosion behaviour of A286 superalloy by using electrochemical potentiokinetic techniques

Martín, Óscar; Tiedra, Pilar De; Blanco, Manuel San Juan

doi:10.1016/j.matdes.2015.08.041

Cited by 23 publications

(14 citation statements)

References 27 publications

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“…The cast ingots were cut into square test coupons with dimension of 8 mm Â 8 mm Â 3 mm using a water-cooled wire cutting machine for microstructural analysis. Standard heat treatment [1,15,18] (homogenized at 1180 C for 5 h, solid-solutioned at 900 C for 2 h, and aged at 720 C for 16 h as shown in Figure 1) was performed for the samples under argon protection. Microstructure and phase identification of heat-treated A286 superalloys were subsequently characterized by means of an optical microscope (OM; Leica DMi8 A), scanning electron microscope (SEM-Supra 55) equipped with an energy dispersive spectroscopy (EDS).…”

Section: Composition Selection and Experimental Proceduresmentioning

confidence: 99%

“…To enhance the strengthening mechanism at sufficient high temperatures, TiC particles are widely used in the austenite matrix as a reinforcement, [ 16,17 ] which can limit the formation of chromium‐rich M 23 C 6 ‐type carbide at grain boundaries, can prevent intergranular stress corrosion, and can increase the tensile and creep strength at both high and low temperatures. [ 18,22 ] Ti is the primary constituent of A286 alloy, particularly in the precipitates. Variations in Ti content in the alloy have a direct impact on the formation of η and TiC.…”

Section: Introductionmentioning

confidence: 99%

“…Finding a suitable ratio of constituent elements, especially Ti and Al, is required to give the highest strengthening effect at higher temperature works for a long time. [8][9][10][11][12][13][15][16][17][18] Moreover, it is well known that the addition of C is required in some alloys to enhance hardness, [19] but elemental C can cause brittleness during composition setting. If C and Ti are added in a certain ratio, they can combine with each other to form into TiC, which acts as a reinforcement ceramic particles and has a beneficial effect by enhancing the strengthening mechanism in alloys.…”

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confidence: 99%

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Effect of Carbon and Titanium Variations in Fe‐Based Heat‐Resistant Superalloy A286 on TiC and η Phase Formation

Qurashi

Zhao

Chen

et al. 2022

steel research int.

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A286 super austenitic stainless steel is a kind of superalloy containing large amounts of Ni and Cr and small amounts of Ti (1-3%), C (0-0.06%), Al (0.1-0.3%), Mn (0.5-1.5%), and Co (0-0.5). [1] Similar to Ni-based superalloys in microstructure, this alloy is strengthened by age-hardening. As a heat-resistant superalloy, it has been designed for applications requiring sufficiently high creep fracture strength and excellent fatigue resistance at temperatures as high as 700 C. Typical areas of applications include aircraft engines, turbine wheels and blades, fasteners and springs, etc. [2][3][4][5][6] In this alloy, eta (η) Ni 3 Ti hcp phase is a stable phase which is formed from the dissolution of γ 0 phase [7][8][9] at aging temperatures in the range of 600 850 C. [10][11][12][13] Some researchers stated that during prolonged hotworking above 720 C, η phase can easily precipitate at grain boundaries from the fcc austenitic matrix, [14] which can have a direct influence on the creep behavior of the alloys. [15,16] Depending on the chemical composition and heat treatment conditions, η and carbide phases precipitate simultaneously or sequentially in this alloy system.Many efforts have been made by researchers to find a suitable composition which can enhance the strengthening mechanism by proper control of eta (η) phases up to some extent at high temperature by the addition of alloying elements. Finding a suitable ratio of constituent elements, especially Ti and Al, is required to give the highest strengthening effect at higher temperature works for a long time. [8][9][10][11][12][13][15][16][17][18] Moreover, it is well known that the addition of C is required in some alloys to enhance hardness, [19] but elemental C can cause brittleness during composition setting. If C and Ti are added in a certain ratio, they can combine with each other to form into TiC, which acts as a reinforcement ceramic particles and has a beneficial effect by enhancing the strengthening mechanism in alloys. [16,17] Strengthening mechanism by TiC reinforcement particles has been widely studied in different stainless steel alloys, especially 300 and 400 series, [20,21] but not well studied in A286 heatresistant alloys.To enhance the strengthening mechanism at sufficient high temperatures, TiC particles are widely used in the austenite matrix as a reinforcement, [16,17] which can limit the formation of chromium-rich M 23 C 6 -type carbide at grain boundaries, can prevent intergranular stress corrosion, and can increase the tensile and creep strength at both high and low temperatures.

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Section: Composition Selection and Experimental Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of Carbon and Titanium Variations in Fe‐Based Heat‐Resistant Superalloy A286 on TiC and η Phase Formation

Qurashi

Zhao

Chen

et al. 2022

steel research int.

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“…A286 is an austenitic superalloy which is widely used in manufacturing disks and shafts in the gas turbine industry due to its good thermal resistance and superior mechanical properties [1,2]. When joining these rotational components (i.e., rods and tubes) with high qualities, rotary friction welding (RFW) is the best choice for its outstanding characteristics such as high reliability, low cost, and excellent properties [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Structural response of A286 superalloy to rotary friction welding at different rotation speed

Jin

Chen

et al. 2020

Mater. Res. Express

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Rotary friction welding was conducted on A286 with a diameter of f25 mm under 300, 900 and 2100 rpm to understand the structural response of the joint welded at different rotation speeds. Joint morphologies, grain structures inside the morphologies and the corresponding mechanism that governs its formation were characterized and investigated using electron backscattered diffraction (EBSD), which focused on three featured zones located at the center, 1/2R and periphery of the joint. The influence of structural response on joint properties was also investigated. Results show that the morphology of the joint evolves from 'disk shape' to 'near-line shape' and 'scissors shape' as the rotation speed increases from 300 rpm to 2100 rpm. At low rotation speed, refined and recrystallized grains were formed inside disk shape morphologies. Whereas, sub-grains and deformed grains were evolved at the middle (900 rpm) and high (2100 rpm) rotation speed. The recrystallized grains surrounded by the 'disk shape' morphology have a positive effect on the joint strength compared with the sub-grains and deformed grains confined by the 'near-line shape' and 'scissors shape' morphologies.

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“…A286 superalloy is strengthened by the precipitation of the ordered fcc g' phase (Ni 3 (Al,Ti)), coherent with the austenite matrix [2][3][4]. The g' phase is unstable and, after a sufficiently long aging treatment at sufficiently high temperature, dissolves to form the stable hcp h phase (Ni 3 Ti) [4][5][6][7]. The h phase may precipitate at grain boundary by cellular reaction at lower aging temperatures, or into the grain with Widmanstätten morphology at higher aging temperatures [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Effect of Widmanstätten η phase on tensile shear strength of resistance spot welding joints of A286 superalloy

Martín

Tiedra

Blanco

2019

Metall. Res. Technol.

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This work aims to study the effect of Widmanstätten h phase on tensile shear strength (TSS) of resistance spot welding joints (RSW) of A286 superalloy subjected to post-weld high temperature aging treatment. The tensile shear test specimens were welded in the solution treated condition, and then subjected to six different post-weld aging treatments (at an aging temperature of 840°C for six different aging times). The ascast dendritic microstructure of the weld nugget and the austenite equiaxed-grain microstructure of the base metal have a different response to the post-weld high temperature aging treatment. Growth of Widmanstätten h phase in the weld nugget is faster than in the base metal. While in the base metal the Widmanstätten h phase precipitates into the grain, in the weld nugget precipitates at the interdendritic region because of the segregation of Ti towards the last-to-solidify interdendritic regions (studied by performing SEM/EDX analysis). Although the hardness increases with the presence of Widmanstätten h phase, the increase in hardness does not necessarily imply an increase in the experimental TSS.

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Study of influence of gamma prime and eta phases on corrosion behaviour of A286 superalloy by using electrochemical potentiokinetic techniques

Cited by 23 publications

References 27 publications

Effect of Carbon and Titanium Variations in Fe‐Based Heat‐Resistant Superalloy A286 on TiC and η Phase Formation

Effect of Carbon and Titanium Variations in Fe‐Based Heat‐Resistant Superalloy A286 on TiC and η Phase Formation

Structural response of A286 superalloy to rotary friction welding at different rotation speed

Effect of Widmanstätten η phase on tensile shear strength of resistance spot welding joints of A286 superalloy

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