Effect of yttrium on microstructure and properties of Ni3Al base alloy IC6

Yan, Han; Xiao, Chengbo

doi:10.1016/s0966-9795(99)00139-9

Cited by 34 publications

(17 citation statements)

References 13 publications

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“…Regarding the improvement of the oxidation resistance by the Y addition, there are many previous works [16,27,29,42] that support the conclusion. In most cases, the Y addition reduces the weight gain during oxidation and decreases the parabolic rate constants as well.…”

Section: Discussionsupporting

confidence: 60%

“…[3,4,5] A great deal of research work has been carried out in the last decade to investigate the effect of alloying on mechanical properties and improve the oxidation-resistance behavior of the ␥-TiAl-based alloys by adding ternary and quaternary elements. [6][7][8][9][10][11][12][13][14][15][16] Among alloying elements, the addition of Mn improves the room-temperature ductility by activating mechanical twinning, while Mo is known to enhance the high-temperature strength. [17,18,19] Nb appears to improve the high-temperature oxidation resistance of TiAl-based alloys.…”

Section: Introductionmentioning

confidence: 99%

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Development and elemental powder metallurgy of a Y-containing two-phase TiAl alloy

Hwang

Morris

2003

Metall Mater Trans A

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The Y modification of a two-phase (␥ ϩ ␣ 2 ) TiAl-(Mn,Mo,C) alloy was studied with an aim to improve, mainly, the oxidation resistance and the mechanical properties in a high-temperature air environment. The experimental alloy was prepared by the elemental powder metallurgy (EPM) method. The addition of up to 0.6 at. pct Y resulted in a significant improvement in tensile properties and compressive yield strength and an anomalous yielding phenomenon withal. Two structural characteristics were identified: first, microstructural refinement in terms of the grain size as well as the interlamellar spacing, and second, precipitation of fine oxides that might scavenge harmful oxygen. Deformation was found to be mainly provided by 1/2͗110] ordinary dislocations and a much lesser amount of ͗011] superdislocations as compared to what has been reported in other (␥ ϩ ␣ 2 ) TiAl alloys. The oxidation resistance of the experimental alloy was evaluated by air-exposure tests at 800°C, from which the oxidation kinetics and the morphological and phase characteristics of the oxide scales were analyzed. With a Y addition, the constituents of the oxide scale changed from those of the Y-free alloy. In the case of the Y-free alloy, the oxide scale which formed upon extended air exposure (350 hours) at 800°C consisted of a mixture of TiO 2 and ␣-Al 2 O 3 . In the case of the alloy modified with Y (0.6 at. pct), however, the oxide scale formed in an identical environment was considerably different: it consisted of a complex mixture of

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Section: Discussionsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Development and elemental powder metallurgy of a Y-containing two-phase TiAl alloy

Hwang

Morris

2003

Metall Mater Trans A

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“…Similar studies were reported by several researchers in various alloy systems which support this conclusion. [21][22][23][24][25] In most cases, Yadditions reduce the weight gain during oxidation and decrease the parabolic rate constant. Zhang et al 21) studied the oxidation resistance of a H13 steel implanted with yttrium or yttrium plus carbon, and concluded that yttrium provided a barrier layer for hindering the oxygen diffusion along dislocations or grain boundaries during thermal oxidation.…”

Section: Discussionmentioning

confidence: 99%

“…Tsai et al 22) found that yttrium atoms segregated along grain boundaries and hindered both anionic and cationic intergranular diffusion in Ni-30Cr alloy. In Ni 3 Al-based alloys with yttrium additions, Han et al 25) investigated the mechanism of improvement of high temperature isothermal oxidation resistance and indicated that this resistance of the alloy was substantially improved by the proper amount of yttrium. They demonstrated that the beneficial effects of yttrium on high temperature oxidation resistance included: (a) inhibiting the cationic transportation and decreasing the depth of the diffusion layer, (b) promoting the selective oxidation of aluminum and (c) promoting the formation of a fine and closely-packed oxide grain structure.…”

Section: Discussionmentioning

confidence: 99%

“…[3][4][5][6][7][8][13][14][15][16][17][18] In our previous studies, it has been found that yttrium is a good alloying element to improve the mechanical properties and oxidation resistance without sacrificing the ductility of TiAl-based alloys. 19,20) Also several investigators have studied the effect of yttrium addition as a metallic constituent, and the high temperature oxidation behavior of alloy systems other than TiAl [21][22][23][24][25] and have found that yttrium addition is beneficial. Therefore, yttrium is an attractive element with which to study the oxidation resistance of TiAl-based alloys.…”

Section: Introductionmentioning

confidence: 99%

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High-Temperature Oxidation Behavior of Elemental Powder Metallurgy Processed TiAl-Mn-Mo-C Alloys with Yttrium Addition

Hwang

Umakoshi

2004

Mater. Trans.

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Effects of yttrium addition on the formation of oxide scales and the oxidation resistance of elemental powder metallurgy (EPM) processed TiAl-Mn-Mo-C alloys were studied. The Y-containing TiAl-based alloys (0:1$0:6 at%Y) showed better oxidation resistance than Y-free alloy oxidized in air at 800C for 350 h. The Y-containing alloys showed a significantly reduced weight gain, especially for 0.6 at%Y-added alloy. In the Y-free alloy, the scale formed during extended air-exposure at 800 C consisted of TiO 2 and -Al 2 O 3 . For 0.6 at%Y-added alloy, however, the oxide scale was composed of a complex mixture of TiO 2 , -Al 2 O 3 , Y 2 O 3 and Al 5 Y 3 O 12 . The formation of multi-phase (Y, Al)O-type oxides layer in a transitional Y-rich subscale close to the substrate and an increase of the amount of -Al 2 O 3 in the mixture oxide layer in the Y-added alloys were the main contributor to improving the oxidation resistance of the alloys. The reduction of oxygen content in the substrate also had a beneficial effect on the oxidation resistance of the Y-containing TiAl-based alloys.

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Effects of Y and La Additions on the Processing and Properties of a Second Generation Single Crystal Nickel‐Base Superalloy CMSX‐4®

et al. 2012

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The effects of yttrium and lanthanum additions on the processing and properties of a second generation single crystal nickel-base turbine blade superalloy CMSX-4  are investigated. The additions of Y and La at 20 ppm Y+La did not have a significant effect on the as-cast microstructure; while at 65 and 350 ppm, the appearance of Y and La-rich phases becomes increasingly apparent. The partitioning of the major alloying elements was unaltered by the rare-earth additions as shown by EPMA mapping carried out on as-cast samples. However, DSC studies indicate that the as-cast incipient melting temperatures were progressively lowered with increasing Y+La additions. Subsequent solution heat treatment trials therefore showed increased susceptibility to incipient melting for alloys with 65 and 350 ppm Y+La. Alloy stability studies carried out at 1000°C and 1100°C indicate increased propensity to TCP phases formation with Y+La additions of up to 65 ppm; while at 350 ppm Y+La, the occurrence of TCP phases appeared to decrease. It appears that the implementation of Y and La additions to single crystal turbine blades has to be carried out carefully to balance the improvements which may be obtained in oxidation/environmental protection performance against the potential issues related to processing e.g. solution heat treatment, and metallurgical issues such as alloy stability.

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Effect of yttrium on microstructure and properties of Ni3Al base alloy IC6

Cited by 34 publications

References 13 publications

Development and elemental powder metallurgy of a Y-containing two-phase TiAl alloy

Development and elemental powder metallurgy of a Y-containing two-phase TiAl alloy

High-Temperature Oxidation Behavior of Elemental Powder Metallurgy Processed TiAl-Mn-Mo-C Alloys with Yttrium Addition

Effects of Y and La Additions on the Processing and Properties of a Second Generation Single Crystal Nickel‐Base Superalloy CMSX‐4®

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