Dilatometric analysis on shrinkage behavior during non-isothermal sintering of nanocrystalline tungsten mechanically alloyed with molybdenum

The paper attempts to study the shrinkage behavior of nanocrystalline tungsten mechanically alloyed with molybdenum (5, 10, 15 and 20 wt.%). The dilatometric analysis was performed by Setsys Evolution TMA (ambient to 1600 °C) using constant heating rate (CHR) method. The significant improvement in shrinkage with alloying of molybdenum is attributed to reduced grain size, lowered tungsten carbide contamination and enhanced diffusion kinetics. The initial stage sintering kinetics of W–20Mo alloy has been investigated. The densification starts with Mo diffusion (calculated activation energy = 128 kJ/mol) and proceeds with the diffusion of both along the grain boundaries (calculated activation energy = 307 ± 1 kJ/mol).

► Alloying with Mo reduces the WC contamination during milling.
► Kirkendall effect assisted enhanced diffusion influences the densification of W–Mo alloys
► Densification kinetics improved with Mo alloying in nanocrystalline tungsten.
► Densification starts with Mo diffusion and later W and Mo both diffuse along the grain boundaries.