Metals
·
2023
·Vol. 13
·期 8
·1436
·
IF 2.9
Jialong Kang,Yaoran Cui,Dapeng Zhong,Guibao Qiu,Xuewei Lv
Due to TiAl alloys’ excellent properties, TiAl alloys have received widespread attention from researchers. However, the high energy consumption and lengthy process of traditional preparation methods have always limited the large-scale application of TiAl alloys. This article develops a new method for preparing TiAl-based alloy powder via the magnesium thermal reduction of TiO2in AlCl3-KCl molten salt. In this study, the proportion of AlCl3&KCl molten salts was determined. We conducted phase analysis on the final product by studying the changes in temperature and time. It was found that the TiAl3alloy powder could be obtained by being kept at 750 °C for 2 h, with an oxygen content of 3.91 wt%. The reaction process for the entire experiment was determined through thermodynamic calculations and experimental analysis, and the principles of the reduction process are discussed.Keywords:TiAl alloy;magnesium reduction;AlCl3-KCl;TiO2
研究领域:
材料科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Haoran Li,Yan Liu,JinJing Yang,Ming Yuan,Anle Sun,Tiesong Lin,Xuejian Liu,Zhengren Huang
A new La 2 O 3 -doped Y 2 O 3 crucible materials was fabricated and evaluated by TiAl alloys melting test. Microstructure and properties of the La 2 O 3 -doped Y 2 O 3 ceramics were systemically investigated. In addition, interfacial reaction mechanism of the La 2 O 3 -doped Y 2 O 3 crucible materials and TiAl alloys, together with oxygen content of TiAl alloys were discussed. Solid solution of La 3+ in the crystal lattice of Y 2 O 3 significantly improved sintering properties of the La 2 O 3 -doped Y 2 O 3 crucible materials and decreased the open porosity. Compared with pure Y 2 O 3 , when adding 15 wt% La 2 O 3 , the open porosity and strength retention ration after thermal shock test of the La 2 O 3 -doped Y 2 O 3 crucible materials changed from 10.8% to 3.9% and from 64% to 78%, respectively. The interfacial reaction between La 2 O 3 -doped Y 2 O 3 crucible materials and TiAl alloys belongs to physical dissolution, and no reaction products were found during the melting of TiAl alloys. When using the 15 wt% La 2 O 3 -doped Y 2 O 3 crucible materials to melt TiAl alloys, oxygen content of the TiAl ingot declined to 530 ppm, which was only one fourth of that using pure Y 2 O 3 materials.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2022
·
IF 4.537
Z. Sun,X.X. Zhu,H.Z. Chen,L.X. Zhang
To address the excessive formation of brittle compounds when brazing TiAl alloys, a TiZrHfCoNiCu high-entropy brazed filler was developed to realize the brazing of TiAl/Ti 2 AlNb couples. The TiAl/Ti 2 AlNb brazed joints can be divided into 4 zones, i.e., 2 diffusion zones at the TiAl/braze filler, Ti 2 AlNb/braze filler interfaces and 2 zones divided inside the brazed seam. α 2 + γ-TiAl were the main reaction products formed at the TiAl/braze filler interface and α 2 + Ti 0.5 Al 0.12 Nb 0.38 were the main reaction products at the Ti 2 AlNb/braze filler interface. Effects of brazing temperatures on the interfacial microstructure and mechanical properties of the TiAl/Ti 2 AlNb brazed joints were investigated. When brazing at 1100°C/15 min, the highest shear strength can reach 157 MPa (room temperature), and 123 MPa (650°C) respectively. The relationship between the microstructure and the corresponding mechanical response were discussed in detail. This research can offer new insights on developing desirable brazing filler when joining TiAl and TiAl based alloys.
研究领域:
材料科学
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焊接工程
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产品关联
DOI
高影响因子
CORROSION SCIENCE
·
2018
·
IF 4.862
Lian-Kui Wu,Wei-Yao Wu,Jia-Lin Song,Guang-Ya Hou,Hua-Zhen Cao,Yi-Ping Tang,Guo-Qu Zheng
Thickness controllable SiO 2 film was prepared on γ-TiAl alloy by cathodic electrodeposition . The oxidation behaviour of the specimens at 900 °C was studied. The effects of SiO 2 electrodeposition parameters, such as electrolysis time and deposition current density, on the morphology, structure and high temperature oxidation performance of the film were investigated. Results shown during thermal oxidation, the electrodeposited SiO 2 film could react with the TiAl alloy to form an alumina- and silicon-enriched glass-like oxide scale, which can prevent the inward diffusion of oxygen from air to the film/alloy interface, resulting in the remarkable decreased oxidation rate of the alloy.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Yun-Yang Li,Hao-Jie Yan,Ruo-Zhan Yin,Qing-Qing Sun,Lian-Kui Wu,Fa-He Cao
In this work, SiOC coatings incorporated with Ni nanoparticles were fabricated on γ-TiAl alloy by dip-coating. The microstructure and high temperature oxidation behavior of the SiOC-Ni coatings with different Ni contents were investigated. Results showed that the incorporation of Ni nanoparticles improved the oxidation resistance of the SiOC coating at 850 ℃. During thermal exposure to air, the incorporated Ni particles would react with both oxygen and the SiOC coating, forming NiO and Ni 2 Si, respectively, therefore changing the structure of the SiOC coating. The generation of NiO and Ni 2 Si is beneficial in reducing the oxygen partial pressure at the coating/substrate interface, thereby facilitating the formation of a protective aluminum oxide layer.
研究领域:
材料科学
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表面工程
✓ 已验证
产品关联
DOI
高影响因子
CORROSION SCIENCE
·
2018
·
IF 4.862
Lian-Kui Wu,Jing-Jia Wu,Wei-Yao Wu,Guang-Ya Hou,Hua-Zhen Cao,Yi-Ping Tang,Hui-Bin Zhang,Guo-Qu Zheng
A novel Si-Al composite coating was prepared on γ-TiAl alloy by a two-step method. Firstly, an aluminizing coating was fabricated on γ-TiAl alloy via pack cementation technique. Then a SiO 2 coating was prepared on this aluminizing coating via cathodic electrodeposition. The high temperature oxidation resistance of this composite coating was evaluated under 1000 °C. During the oxidation process, this Si-Al composite coating can react with TiAl and prevent the inward diffusion of oxygen from air to the film/alloy interface, resulting in the remarkable decreased oxidation rate of the alloy.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2023
·
IF 6.4
Yun-Yang Li,Hao-Jie Yan,Lian-Kui Wu,Fa-He Cao
To improve the high temperature oxidation resistance of TiAl alloy, silicon oxycarbide (SiOC) coating was fabricated by dip-coating using polydimethylsiloxane (PDMS) as the precursor. The oxidation behavior of the coating was evaluated at 850 °C. The morphology and chemical structure of the SiOC coating were characterized by scanning electron microscopy (SEM) equipped with an energy dispersive spectroscopy (EDS), Fourier Transform infrared spectroscopy (FT-IR), X-ray photo electron spectroscopy (XPS), and X-ray diffraction (XRD). Results showed that the SiOC coating exhibited good oxidation resistance. During the thermal exposure, the selective oxidation of Al at the SiOC/TiAl alloy interface resulted in the generation of protective Al 2 O 3 , which suppressed the inward diffusion of oxygen and outward diffusion of the alloy matrix elements. However, the cracks on the surface of SiOC coating were observed, which would provide channels for the oxygen and form thermally grown oxide layer (mainly consisting of TiO 2 and Al 2 O 3 ) above the Al 2 O 3 layer.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Pei Ren,Meiqi Han,Xingan Wang,Mu Zhang,Xudong Sun
Y 2 O 3 and CaO are ideal ceramic materials for precision casting of TiAl alloy, overcoming challenges associated with intricate component removal, such as turbine blades, leveraging the stability of Y 2 O 3 and the water solubility of CaO. To address these challenges, we employed Isobam104 in a novel gel casting method, serving as both a dispersant and a gelling agent. This method enabled us to create a stable Y 2 O 3 –CaCO 3 slurry with high solid content (up to 55 vol%) and low viscosity (101.51 mPa·s at a shear rate of 10 s −1 ). Following sintering at 1500 °C for 2 h, Y 2 O 3 –CaO composite ceramics were produced. Surprisingly, two distinct characteristics of CaO were noted. One showed a rod-shaped morphology with high chemical reactivity crucial for water solubility, while the other displayed a flat-like feature, forming a well-maintained interface due to its coherent or semi-coherent matching relationship with Y 2 O 3 , thereby providing excellent hydration resistance. Ultimately, we acquired composite ceramics showcasing a 30-day “shelf life" alongside exceptional water solubility. This establishes the theoretical groundwork for storing and employing soluble ceramic cores in the precision casting of TiAl alloy.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
ACTA MATERIALIA
·
2025
·
IF 9.3
Yanjun Liu,Yu Pan,Ranpeng Lu,Aihua Yu,Shuya Zhao,Jianzhuo Sun,Xin Lu
Improving the room-temperature ductility of TiAl alloys is crucial for their broader structural applications. However, excessive interstitial oxygen (O) contamination intensifies the strain incompatibility between α 2 and γ phases, severely impairing the overall mechanical properties. Here, we propose a novel calcium (Ca)-based O-scavenging strategy to enhance the ductility of powder metallurgy (PM) TiAl alloys by introducing trace CaH 2 . A duplex oxide layer composed of outer Al 2 O 3 layer and inner TiO 2 layer, was identified on the surface of TiAl powder and has the thickness of ∼9.13 ± 0.35 nm. Upon the dissolution of oxide layer (∼824°C), O is released and readily diffuses into the matrix as interstitials, where it becomes effectively irretrievable. CaH 2 can react with the oxide layer below its decomposition temperature (∼791°C), effectively immobilizing O as nanoscale CaO particles, thereby suppressing O dissolution into α 2 phase and mitigating the lattice distortion. The resulting purification of the α 2 phase decreases the critical resolved shear stress (CRSS) required for basal slip. During deformation, deformation twins in the adjacent γ grains facilitate the activation of -type dislocations within α 2 phase, thereby enhancing its plasticity and improving interphase strain compatibility. Additionally, the in-situ formed CaO particles contribute to the dispersion strengthening. As a result, this trace Ca-based deoxidation strategy nearly doubles the room-temperature total elongation of PM Ti4822 alloys while retaining an ultimate tensile strength of 580 MPa, even at a relatively high O content (∼1520 ppm).
研究领域:
材料科学
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金属学与冶金工程
·
结构材料
·
粉末冶金
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力学性能
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位错理论
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相变与组织调控
✓ 已验证
产品关联
DOI
高影响因子
CORROSION SCIENCE
·
2020
·
IF 6.479
Lian-Kui Wu,Jing-Jia Wu,Wei-Yao Wu,Hao-Jie Yan,Mei-Yan Jiang,Fa-He Cao
To improve the hot corrosion resistance, thickness controllable SiO 2 coating was electrodeposited on TiAl alloy. The hot corrosion behavior of the specimens contaminated with 75 wt.% Na 2 SO 4 + 25 wt.% NaCl salt mixture was investigated at 700 °C. Results showed that the generation of compact amorphous SiO 2 embedded with Na 2 Si 4 O 9 and cristobalite was responsible for the enhanced hot corrosion resistance. Moreover, the SiO 2 coating does not only act as a diffusion barrier to sulfur and chlorine but also decreases the oxygen partial pressure at the coating/alloy interface, therefore promoting the selective oxidation of Al to form protective Al 2 O 3 layer.
研究领域:
材料科学
·
腐蚀工程
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）