Influence of nanostructured FeAl powder addition on mechanical properties of WC composites produced by Spark plasma sintering technique

In this study, a FeAl powder synthesized by mechanical alloying and annealing process was used as a binder to produce WC-FeAl composite. The powders of WC and FeAl were blended with composition of WC-25 vol% FeAl and sintered by spark plasma sintering at 1150℃. The hardness, fracture toughness and wear behavior of sintered WC-FeAl sample was investigated and compared with a commercial WC-Co. Structural evaluation of mixed powder was showed a homogeneous distribution of WC and FeAl which related to particle size of FeAl to be in the range of 50-800 nm. FeAl nanoparticles were able to diffuse faster between WC particles and occupy interparticle spaces among larger particles in the sintering condition; thus resulted to formation of an almost homogeneous structure with densification to near theoretical density. The hardness and fracture toughness of WC-FeAl was 17.90 GPa and 9.1 MPa√m, respectively that this hardness was higher than that of WC-Co (15.7 GPa) and fracture toughness was lower slightly. The results for wear test showed that the specific wear rate of both samples was enhanced with increasing the test temperature from room temperature to 500℃. Furthermore, WC-FeAl showed higher wear resistance than WC-Co at both room and 500℃ temperatures.