Synthesis of NiAl-WC composite by the thermal explosion of elemental powders

摘要

In this work, NiAl-WC composite was synthesized by a mechanical activated thermal explosion process from the powder mixture of nickel, tungsten, aluminum, and graphite. The phase, morphology, and microstructure development during milling and after the thermal explosion process were evaluated by XRD, FE-SEM, and TEM-EDS analysis techniques, respectively. The results indicated that after the thermal explosion of an as-mixed powder mixture, unreacted starting powder remained, and some new phases like Al0.42Ni0.52 and W2C formed, which confirmed that the synthesis reactions were not completed. But, the final product of 5 h milled powder after the thermal explosion consisted of desired phases, NiAl and WC. XRD results of 5 h milled powder showed that the mechanical activation had two effects on NiAl-WC composite synthesis, reduction of crystallite and particle size, and better mixing of reactant powders and formation of W2C phase as an intermediate phase. These effects increased kinetics of reactions, and finally, NiAl-WC composite formed.