Microstructural stability of long term aging treated Ti–22Al–26Nb–1Zr orthorhombic titanium aluminide

Zhang, Tiebang; Huang, Gang; Hu, Rui; Li, Jinshan

doi:10.1016/s1003-6326(15)63874-2

Cited by 12 publications

(4 citation statements)

References 33 publications

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“…Overall, the aging process involved the transformation of B2 → O. However, the content of O phase fluctuated at the early stage of aging, and tended to be stable (≈80 vol%) when the aging time was over 1 h. This could be attributed to the solution and re‐precipitation of O phase, and further evidence could be traced from SEM images.…”

Section: Resultsmentioning

confidence: 89%

Microstructure and Mechanical Properties of Ti₂AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Cai

Liu

et al. 2017

Adv Eng Mater

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Ti 2 AlNb-based alloys are synthesized by spark plasma sintering from prealloyed and ball-milled Ti-22Al-25Nb powder, and the structure of the alloys is regulated by aging at 800 C for 0.5, 1, 2, and 3 h. Comparison of phase composition, microstructure, and mechanical properties are made in this study. Aging in the B2 þ O phase region refers to the reversible transformation of B2 $ O. Complete B2 þ O Widmanstätten structure is obtained in the aged alloys synthesized from pre-alloyed powder, and the ones from milled powder contain acicular O and B2 þ O Widmanstätten structure. Ball milling eliminates the B2 þ O colonies, facilitates the continuous transformation of O ! B2, and induces acicular O in the alloys; however, the hardness of these alloys is decreased in contrast with that of the ones synthesized from prealloyed powder. Owing to the precipitation strengthening based on a large amount of fine O-phase precipitates, the 3 h aged alloy from pre-alloyed powder exhibits comprehensive mechanical properties with Vickers hardness of 448 AE 9 HV, ultimate tensile strength of 730 MPa, and elongation of 0.43%.

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Section: Resultsmentioning

confidence: 89%

Microstructure and Mechanical Properties of Ti₂AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Cai

Liu

et al. 2017

Adv Eng Mater

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“…Additional alloying elements are usually added to improve properties of the alloy. For example, a combination of Mo and Si is added to improve creep strength and oxidation resistance of the material [22][23][24]. The addition of several atomic percent of other β-stabilizing elements, such as V, Hf, Ta, and W, is often used to increase the β/B2 phase-field resulting in improved workability of the alloy but an increased density [25,26].…”

Section: Introductionmentioning

confidence: 99%

Processing, Microstructure, and Mechanical Properties of Laser Additive Manufactured Ti2AlNb-Based Alloy with Carbon, Boron, and Yttrium Microalloying

Polozov

Gracheva

Popovich

2022

Metals

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In this work, Ti-22Al-23Nb-0.8Mo-0.3Si-0.4C-0.1B-0.2Y (at. %) alloy powder was used to fabricate the Ti2AlNb-based alloy samples using Laser powder bed fusion (L-PBF) Additive Manufacturing with a high-temperature substrate preheating. L-PBF process parameters, including laser power, scan speed, hatching distance, and preheating temperature, allowing for obtaining fully dense (99.9% relative density) crack-free samples, were determined. The effects of substrate preheating temperature during the L-PBF process on microstructure, phase composition, and properties of the obtained Ti2AlNb-based alloy were investigated using X-ray diffraction, scanning electron microscopy, electron backscatter diffraction analysis, and microhardness testing. The results obtained for the material with C, B, and Y microalloying were compared to the Ti2AlNb-based alloy fabricated by L-PBF from the powder not alloyed with C, B, and Y. The results revealed that the microalloying reduced the number of solidification cracks; however, no significant microstructural changes were observed, and high-temperature substrate preheating was still necessary to suppress cold cracking of the alloy. The microstructure of the alloy varied from fully-β/B2, B2 + O, to fully-O depending on the preheating temperature. Effects of hot isostatic pressing and heat treatment conditions on microstructure and mechanical properties were investigated.

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“…Ti-22Al-25Nb (at. %) is one of the most-investigated Ti 2 AlNb-based alloys, but alloying with Mo, Zr, W, and Si is needed to improve its oxidation resistance and creep strength [ 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Mitigating Inhomogeneity and Tailoring the Microstructure of Selective Laser Melted Titanium Orthorhombic Alloy by Heat Treatment, Hot Isostatic Pressing, and Multiple Laser Exposures

et al. 2021

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Titanium orthorhombic alloys based on intermetallic Ti2AlNb-phase are attractive materials for lightweight high-temperature applications. However, conventional manufacturing of Ti2AlNb-based alloys is costly and labor-consuming. Additive Manufacturing is an attractive way of producing parts from Ti2AlNb-based alloys. High-temperature substrate preheating during Selective Laser Melting is required to obtain crack-free intermetallic alloys. Due to the nature of substrate preheating, the temperature profile along the build height might be uneven leading to inhomogeneous microstructure and defects. The microstructural homogeneity of the alloy along the build direction was evaluated. The feasibility of mitigating the microstructural inhomogeneity was investigated by fabricating Ti2AlNb-alloy samples with graded microstructure and subjecting them to annealing. Hot isostatic pressing allowed us to achieve a homogeneous microstructure, eliminate residual micro defects, and improve mechanical properties with tensile strength reaching 1027 MPa and 860 MPa at room temperature and 650 °C, correspondingly. Annealing of the microstructurally graded alloy at 1050 °C allowed us to obtain a homogeneous B2 + O microstructure with a uniform microhardness distribution. The results of the study showed that the microstructural inhomogeneity of the titanium orthorhombic alloy obtained by SLM can be mitigated by annealing or hot isostatic pressing. Additionally, it was shown that by applying multiple-laser exposure for processing each layer it is possible to locally tailor the phase volume and morphology and achieve microstructure and properties similar to the Ti2AlNb-alloy obtained at higher preheating temperatures.

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Microstructural stability of long term aging treated Ti–22Al–26Nb–1Zr orthorhombic titanium aluminide

Cited by 12 publications

References 33 publications

Microstructure and Mechanical Properties of Ti₂AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Microstructure and Mechanical Properties of Ti₂AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Processing, Microstructure, and Mechanical Properties of Laser Additive Manufactured Ti2AlNb-Based Alloy with Carbon, Boron, and Yttrium Microalloying

Mitigating Inhomogeneity and Tailoring the Microstructure of Selective Laser Melted Titanium Orthorhombic Alloy by Heat Treatment, Hot Isostatic Pressing, and Multiple Laser Exposures

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Microstructural stability of long term aging treated Ti–22Al–26Nb–1Zr orthorhombic titanium aluminide

Cited by 12 publications

References 33 publications

Microstructure and Mechanical Properties of Ti2AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Microstructure and Mechanical Properties of Ti2AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Processing, Microstructure, and Mechanical Properties of Laser Additive Manufactured Ti2AlNb-Based Alloy with Carbon, Boron, and Yttrium Microalloying

Mitigating Inhomogeneity and Tailoring the Microstructure of Selective Laser Melted Titanium Orthorhombic Alloy by Heat Treatment, Hot Isostatic Pressing, and Multiple Laser Exposures

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Microstructure and Mechanical Properties of Ti₂AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder

Microstructure and Mechanical Properties of Ti₂AlNb‐Based Alloys Synthesized by Spark Plasma Sintering from Pre‐Alloyed and Ball‐Milled Powder