Hardmetals Prepared From Wc-W2c Eutectic Particles And Alcrfeconiv High Entropy Alloy As A Binder

AlCrFeCoNiV high entropy alloy (HEA) was used as a binder for the densification of WC-W2C eutectic particles by spark plasma sintering (SPS) at different sintering temperatures (1000-1400 degrees C). The relationship between phase composition and microstructure of (WC-W2C) - 10 wt% AlCrFeCoNiV metal-matrix composites depending on the sintering temperature was investigated and mechanical properties were determined. The bcc solid solution of HEA binder formed during mixing with WC-W2C by ball milling is metastable in nature and transforms to a mixture of bcc and fcc solid solutions during consolidation by SPS at 1100 degrees C. The increase of sintering temperature to 1200 degrees C and 1400 degrees C resulted in formation of a major bcc phase and a minor fcc phase, which are more thermodynamically stable. It is shown that a partial dissolution of the W2C phase in the HEA matrix occurs at 1000 degrees C. As the sintering temperature increases to 1400 degrees C, the W2C phase completely dissolves, releasing WC plates. As a result, the composites after sintering at 1200-1400 degrees C were free from the (Fe,Co,Ni)(3)W3C phase due to the dissolution of W2C. The highest hardness (HV30) of 15.9-16.4 GPa and Palmqvist toughness of 16.6-17.2 MPa m(1/2 )was achieved in hardmetals SPSed at 1200 degrees C and 1400 degrees C.