Effect of Re on microstructural evolution and densification kinetics during spark plasma sintering of nanocrystalline W

In the present investigation, nanocrystalline W and W-xRe (x = 3, 5 wt.%) alloy powders were produced by mechanical milling/alloying using high energy ball milling. The nanocrystalline nature (similar to 50 nm) of these powders was validated by the Rietveld refinement of their respective X-Ray diffraction patterns. Subsequently, spark plasma sintering of the ball milled powders was carried out. It was observed that pure W was not able to densify completely (relative density of 93%) at a temperature of 1500 degrees C. However, the addition of 5 wt.% Re resulted in near complete densification (relative density of 97%) at the same sintering temperature. The enhanced densification of W-Re powders is mainly attributed to the ductilising effect of Re assisted by the nanocrystallinity of powders, and the application of pressure during sintering. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.