Achieving high strength and ductility in ODS-W alloy by employing oxide@W core-shell nanopowder as precursor

Zhi Dong,Zongqing Ma,Liming Yu,Yongchang Liu

doi:10.1038/s41467-021-25283-2

Zhi Dong, Zongqing Ma + Show 2 more

Open Access

https://doi.org/10.1038/s41467-021-25283-2

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Journal: Nature Communications	Publication Date: Aug 20, 2021
Citations: 93	License type: open-access

Affiliation: Tianjin University

Abstract

With excellent creep resistance, good high-temperature microstructural stability and good irradiation resistance, oxide dispersion strengthened (ODS) alloys are a class of important alloys that are promising for high-temperature applications. However, plagued by a nerve-wracking fact that the oxide particles tend to aggregate at grain boundary of metal matrix, their improvement effect on the mechanical properties of metal matrix tends to be limited. In this work, we employ a unique in-house synthesized oxide@W core-shell nanopowder as precursor to prepare W-based ODS alloy. After low-temperature sintering and high-energy-rate forging, high-density oxide nanoparticles are dispersed homogeneously within W grains in the prepared alloy, accompanying with the intergranular oxide particles completely disappearing. As a result, our prepared alloy achieves a great enhancement of strength and ductility at room temperature. Our strategy using core-shell powder as precursor to prepare high-performance ODS alloy has potential to be applied to other dispersion-strengthened alloy systems.

Highlights

With excellent creep resistance, good high-temperature microstructural stability and good irradiation resistance, oxide dispersion strengthened (ODS) alloys are a class of important alloys that are promising for high-temperature applications
The cWY alloy exhibits about a 75.9% increase in ultimate tensile strength (UTS) when compared with the optimal congeneric W-Y2O3 alloy (TE of 0%) reported in the literatures[27,28,29,30] and 43.8% increase in UTS and 127.3% increase in total elongation (TE) when compared with the optimal W-ZrC alloy reported in the literatures[31,32,33,34]
As for the traditional preparation methods, whether the mechanical alloying or codeposited chemical method, the adscititious oxide particles generally attach to W powders only through physical binding, and the two phases are distinctly separated in the as-mixed state[55]

Summary

Introduction

Good high-temperature microstructural stability and good irradiation resistance, oxide dispersion strengthened (ODS) alloys are a class of important alloys that are promising for high-temperature applications. The high-temperature microstructural stability benefiting from the introduction of second-phase dispersoids further highlights its application superiority[12] In recent decades, both the ex-situ and in-situ methods have been developed to homogeneously introduce the desirable second-phase dispersoids into different metal matrixes[13,14,15]. The nano dispersoids or nanoprecipitates introduced via the in-situ method are mainly synthesized through thermo-mechanical treatment or chemical reaction[15] They generally exhibit good thermodynamic stability, fine size, and uniform distribution in metal matrix[13]. Taking the Al-Sc binary alloy for example, the addition of Zr and Er elements can generally promote the formation of coarsening-resistant coherent L12-Al3(Sc, Zr, Er) nanoprecipitates Their ultrafine size (3–8 nm), results in a prominent strength enhancement from 243 MPa to 451 MPa17,19. The precipitation of coherent B2 nanoparticles (3–5 nm) in a body-centered cubic (BCC) martensite matrix can render a Fe-17Ni-6.2Al-2.3Mo-

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