Microstructure evolution and densification during spark plasma sintering of nanocrystalline W-5wt.%Ta alloy

Abstract

The present work reports the effect of Ta on densification and microstructure evolution during non-isothermal and spark plasma sintering of nanocrystalline W. Nanocrystalline W-5wt.%Ta alloy powder was synthesised using mechanical alloying. The nanocrystalline powder was characterised thoroughly using X-ray diffraction line profile analysis. Furthermore, the shrinkage behaviour of nanocrystalline powder was investigated during non-isothermal sintering using dilatometry. Subsequently, the alloy powder was consolidated using spark plasma sintering up to 1600°C. The role of Ta on stabilising the microstructure during spark plasma sintering of nanocrystalline W was investigated in detail using electron backscatter diffraction. The average grain size of spark plasma sintered W-5wt.%Ta alloy was observed as 1.73 1  µm.

Microstructure and mechanical properties of W-10 wt-%Ta alloys prepared by spark plasma sintering

“…It is preliminarily speculated that the increase of Kirkendall porosity leads to a decrease in densification. Compared with the reports in the literature [36], it is interesting that this kind of expansion occurs at a lower temperature. In other words, tantalum seems to reduce the temperature at which expansion occurs in tungsten materials, and the construction of Kirkendall porosity began earlier.…”

“…This could be explained by enhanced localised heating due to dynamic pore evolution induced point contacts. W-5 wt-%Ta alloy was prepared by high-energy ball milling and SPS [36]. The heating rate was 100 °C min −1 , the dwell period was 5 min, and the temperature was 1600°C.…”

Retention of hydrogen in W-Ti-C, W-Ta-C and W-Zr-C alloys:ab initiostudy

“…Therefore, people focus on how to suppress the formation of void, bubbles and fuzz to improve the anti-irradiation properties of W, and reduce H retention in W. It is extensively found that addition of alloying atoms such as Ti, Ta, and K [12,15,16], and compounds such as TiC, TaC, ZrC, Y 2 O 3 and La 2 O 3 can improve the mechanical properties of W [17][18][19][20][21]. TiC with a melting point of 3140 • C has good thermal stability and thus it is widely added to improve the properties of W. TiC can improve the ductility, and appreciably reduces the DBTT of W to 260 K [17].…”