期刊
出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.msea.2020.139329
关键词
ODS-W; Hydrothermal method; Alkaline condition; Coherent interface
类别
资金
- National Natural Science Foundation of China [51822404, 51574178]
- Science and Technology Program of Tianjin [19YFZCGX00790]
- Natural Science Foundation of Tianjin [18JCYBJC17900]
- Seed Foundation of Tianjin University [2018XRX-0005, 2019XYF-0066]
Oxide dispersion strengthened tungsten (ODS-W) alloys are a class of important materials that widely used for high temperature applications due to their unique physical and mechanical properties. However, the insufficient ductility of ODS-W alloys at low or high temperatures limits their widespread application, especially as structural materials. It is always a great challenge to efficiently disperse oxide second phase nanoparticles within W matrix for achieving ODS-W alloy with excellent balance of strength and ductility. Here we report an innovative strategy for the fabrication of high-performance ODS-W alloy with strength of up to 1134 MPa and total elongation over 30% at 700 degrees C. The innovative route involves the preparation of W-Y2O3 composite powder precursor via alkaline hydrothermal method and subsequent low-temperature sintering in hydrogen atmosphere. The internal flake structure with uniformly dispersed Y component and external coating of W component on this flake structure can be formed in alkaline hydrothermal product and then be passed on to the reduced W-Y2O3 composite nanopowders. As a result, the distribution of second phase oxide particles in the low-temperature sintered alloys using these composite nanopowders as precursor is optimized significantly including an increase in the volume fraction of intragranular oxide particles and a decrease in the size of both intergranular and intragranular oxide particles. Besides, the average W grain size is also refined dramatically (410 nm). More importantly, the intragranular oxide particle / W matrix interface is regulated to be coherent relationship. The combined action of these microstructural factors is responsible for the significantly enhanced strength and ductility of ODS-W alloy. These results indicate that the newly developed alkaline hydrothermal method in our work is a promising way to fabricate high performance ODS tungsten based alloys.
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