Effect of η-phase and FeAl composition on the mechanical properties of WC–FeAl composites

• Oxygen content in WC–FeAl influences α-Al2O3 formation and carbon content.
• The former changes FeAl composition whereas the latter influence η-phase formation.
• A large amount of η-phase degrades the TRS and fracture toughness.
• The increment of Fe ratio in FeAl improves these two mechanical properties.

This study investigated the effects of η-phase generation and the binder phase composition of iron aluminide (FeAl) on the mechanical properties of tungsten carbide–iron aluminide (WC–FeAl) composites. The η-phase was generated in the composites when the WC–FeAl powder was highly oxidized before sintering in a vacuum. The presence of the η-phase resulted in the degradation of mechanical properties such as transverse rupture strength (TRS) and indentation fracture toughness (IFT). In addition, FeAl composition varied mainly as a result of α-Al2O3 formation. The iron-rich side of FeAl in binder phase improved the TRS and IFT. It was concluded that control of the η-phase generation and an appropriate FeAl composition are very important to maintain high TRS and IFT in the WC–FeAl system.

Figure optionsDownload as PowerPoint slide