High-temperature deformation in a Ta–W alloy

Lin, Zhigang; Lavernia, Enrique J.; Mohamed, Farghalli A.

doi:10.1016/s1359-6454(98)00434-0

Cited by 34 publications

(12 citation statements)

References 38 publications

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“…A C C E P T E D M A N U S C R I P T high density, high melting point, low ductile-to-brittle transition temperature and moderately high elastic modulus [1][2][3][4][5]. One particular problem with the Ta and the Ta alloys, however, is the poor oxidation resistance.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Phase relations in the Ta2O5-WO3-SiO2 system

Wang

Chen

Bai

et al. 2017

International Journal of Refractory Metals and Hard Materials

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Section: Accepted Manuscriptmentioning

confidence: 99%

Phase relations in the Ta2O5-WO3-SiO2 system

Wang

Chen

Bai

et al. 2017

International Journal of Refractory Metals and Hard Materials

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“…[34] These second-phase particles are usually found to be 2 to 10 nm in size and play a critical role in retarding grain growth in the nanocrystalline materials [35] and in serving as barriers to dislocation movement, which significantly affects the mechanical properties of materials. [36][37][38][39][40] 1. Effects on thermal stability The formation of nanoscale particles during milling in liquid nitrogen [7] enhances the thermal stability of the material by impeding grain growth during annealing at high temperatures.…”

Section: Influences Of the Nanoscale Dispersion Particlesmentioning

confidence: 99%

“…However, careful examination of many representative TEM micrographs shows that residual loops, which are a characteristic of the interaction between dislocations and dispersion particles in the Orowan model, is not a typical feature of the microstructure of the crept specimens of Zn-22 pct Al. In addition, experimental studies of the creep behavior of alloys containing dispersion particles have consistently shown the presence of threshold stress, [37][38][39][40][43][44][45] and that the value of the threshold stress is reported to be less than the Orowan stress. It has been suggested that the Orowan theory is superseded by theories based on climb of dislocations [46,47,48] (local and general) near the dispersion during high-temperature deformation.…”

Section: Dispersion/dislocation Interactions During High-temperature mentioning

confidence: 99%

Processing and microstructural evolution of powder metallurgy Zn-22 Pct Al eutectoid alloy containing nanoscale dispersion particles

Xun¹,

Rodriguez²,

Lavernia

et al. 2005

Metall Mater Trans A

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The present article deals with the processing and microstructural evolution of powder metallurgy (PM) Zn-22Al pct eutectoid alloy. The powder material was produced through inert gas atomization and then cryomilled in liquid nitrogen. The milled powder particles were consolidated by hot isostatic pressing ("hipping") followed by thermomechanical treatment, resulting in a two-phase microstructure. The microstructures were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The principal processing factors and microstructural characteristics associated with the major processing steps, including spray atomization, mechanical milling (MM), consolidation, and heat treatment, were evaluated and discussed. Hot isostatic pressing and extrusion followed by heat treatment to produce the superplastic structure (Al-rich phase and Zn-rich phase) are effective in elimination porosity. A TEM examination of the microstructure of the alloy after processing reveals the presence of nanodispersion particles that are not uniformly distributed. The formation of the dispersions was attributed to the interaction between the powder material (primarily Al phase) and environmental elements such as oxygen and nitrogen during milling. Moreover, the size and distribution of the dispersions present in the bulk material met the anticipated requirements for serving as inhibitors for grain growth and barriers for dislocation movement. The TEM observations on crept specimens reveal extensive dislocation/dispersion interactions.

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“…Ta-W alloys show a series of desirable properties, such as high density, high melting point, good heat conductivity, good fracture toughness, excellent corrosion resistance and weldability [3]. Besides, compared with some other bcc metals, such as W, Mo, Fe, Nb and their alloys, Ta-W alloys have better cold fabricability and a lower ductile-to-brittle transition temperature [4]. Therefore, they have been excellent candidates for components that operate under mechanical and thermal extremes [5].…”

Section: Introductionmentioning

confidence: 99%