Effects of doping route on microstructure and mechanical properties of W-1.0wt.%La2O3 alloys
(1. Beijing Advanced Innovation Center for Materials Genome Engineering, Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;
2. Grinm Group Co., Ltd., Beijing 100088, China)
2. Grinm Group Co., Ltd., Beijing 100088, China)
Abstract: A comparative study was conducted by using solution combustion synthesis with three different doping routes (liquid-liquid (WL10), liquid-solid (WLNO) and solid-solid (WLO)) to produce nanoscale powders and further fabricate the ultrafine-grained W-1.0wt.%La2O3 alloys by pressureless sintering. Compared with pure tungsten, W-1.0wt.%La2O3 alloys exhibit ultrafine grains and excellent mechanical properties. After sintering, the average grain size of the WLO sample is larger than that of WL10 and WLNO samples; the microhardness values of WL10 and WLNO samples are similar but larger than the value of WLO sample. The optimized La2O3 particles are obtained in the WL10 sample after sintering at 1500 °C with the minimum mean size by comparing with WLNO and WLO samples, which are uniformly distributed either at grain boundaries or in the grain interior with the sizes of (57±29.7) and (27±13.1) nm, respectively. This study exhibits ultrafine microstructure and outperforming mechanical properties of the W-1.0wt.%La2O3 alloy via the liquid-liquid doping route, as compared with conventionally-manufactured tungsten materials.
Key words: tungsten alloy; solution combustion synthesis; doping route; ultrafine grain; microhardness