The influence of heating rate on W-Cr-Zr alloy densification process and microstructure evolution during spark plasma sintering

In this work, W-Cr-Zr as a self-passivating tungsten alloy is studied. Spark plasma sintering (SPS) is used to prepare the sample. The influence of the heating rate on the densification process and microstructure evolution during SPS was investigated. The increasing the heating rate enhance the homogeneity of the microstructure, however, did not show great effect on overall the sample density. High heating rate with high thermal inertia led the actual temperature to approach or even exceed WCr alloy solution temperature. Based on the punch displacement curves, it can be found that the densification temperatures are approximately 1380 °C and the high heating rate could promote the densification rate. On the other hand, high heating rate required high current, which can decrease the sintering activation energy and improve the densification process.