Search

Your search keyword '"Liu, Wensheng"' showing total 241 results
Start Over Author "Liu, Wensheng" Publisher elsevier b.v.
241 results on '"Liu, Wensheng"'

48. Atomic-scale investigation on the evolution of T1 precipitates in an aged Al-Cu-Li-Mg-Ag alloy.

Author

Zhao, Xinyue, Ding, Juan, Xiao, Daihong, Huang, Lanping, and Liu, Wensheng

Subjects
ALUMINUM alloys, PRECIPITATION (Chemistry), TRANSMISSION electron microscopy, TRACE elements, LATTICE constants
Abstract

• An intermediate T 1 ' phase between T 1p and T 1 is discovered. • T 1 ' exhibits different lattice parameters, atomic occupancy, chemical composition and segregation compared to T 1. • Distributions of Ag, Mg and Zn in the precipitates exhibited significant differences. • The shear component involved in the transformation from T 1p to T 1 ' is only 1/12<112> α. • The existence of Al-Li corrugated layer at the T 1 /α interface is verified by iDPC-STEM. The T 1 (Al 2 CuLi) phase is one of the most effective strengthening nanoscale-precipitate in Al-Cu alloys with Li. However, its formation and evolution still need to be further clarified during aging due to the complex precipitation sequences. Here, a detailed investigation has been carried out on the atomic structural evolution of T 1 precipitate in an aged Al-Cu-Li-Mg-Ag alloy using state-of-the-art Cs-corrected high-angle annular dark field (HAADF)- coupled with integrated differential phase contrast (iDPC)-scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDXS) techniques. An intermediate T 1 ' phase between T 1p and T 1 phase, with a crystal structure and orientation relationship consistent with T 1 , but exhibiting different atomic occupancy and chemical composition was found. We observed the atomic structural transformation from T 1p to T 1 ' phase (fcc→hcp), involving only 1/12<112> Al shear component. DFT calculation results validated our proposed structural models and the precipitation sequence. Besides, the distributions of minor solute elements (Ag, Mg, and Zn) in the precipitates exhibited significant differences. These findings may contribute to a further understanding of the nucleation mechanism of T 1 precipitate. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

49. The bifunctional low mismatch nano strengthening phase leads to a high strength-ductility W-Ta-Ni-Fe-Cu alloy.

Author

Wang, Yao, Huang, Yufeng, Chen, Baishan, Zhang, Lei, Fan, Peiyuan, Li, Ziyi, Ma, Yunzhu, and Liu, Wensheng

Subjects
SOLUTION strengthening, TENSILE strength, COPPER, EUTECTIC reactions, DISPERSION strengthening
Abstract

• The ultimate tensile strength of the alloy reaches 1190.39 MPa. • In-situ formation of Ni 3 Ta phase greatly improve the strength of tungsten alloys. • The alloy has excellent toughness, with a total elongation of 20.8 %. • Ni 3 Ta phase and matrix phase have good interface matching relationship. • The rich Cu layer effectively reduces interface mismatch. As a typical tungsten-based composite consisting of tungsten (W) particles and matrix phase, tungsten heavy alloys (WHAs) are extensively utilized in the military due to their exceptional strength and high density. However, the large grain size (>30 µm) of powder metallurgy liquid phase sintered (LPS) WHAs and the low strength of the matrix phase limit the further improvement of the alloy. In this work, high-density ultrafine WHAs were fabricated by two-step low-temperature sintering, and the density of the alloy reached 17 g/cm3 with an average W particle size of 7.81 µm. Additionally, the eutectic reaction between Ni and Ta was controlled to generate dispersed nano-Ni 3 Ta phases in situ in the matrix phase, further improving the strength of the alloy. Under the synergistic strengthening effect of fine-grain strengthening, dispersion strengthening, and solid solution strengthening, the average ultimate tensile strength of the alloy reached 1190.39 MPa. At the same time, the alloy maintained good elongation with a total elongation of 20.8 % due to the good co-grid interface orientation between the Ni 3 Ta phase and the matrix phase. This study provides a new idea for developing high-strength WHAs and has a guiding significance for developing Ni-based alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results