Crystallite size and strain calculations of hard particle reinforced composite powders (Cu/Ni/Fe-WC) synthesized via mechanical alloying

In this study, Cu-25WC, Ni-25WC, and Fe-25WC (all in wt%) composite powders were produced via mechanical alloying (MA) and characterized for their potential utilization in particulate materials based technologies. The changes in the crystallite size (D) and lattice strain (epsilon) during the production of WC particle reinforced Cu, Fe, and Ni composite powders via MA were investigated. The Williamson-Hall (W-H) plot analysis and fundamental parameters approach (FPA) applied with Lorentzian function were used to evaluate epsilon and D of matrix phases from XRD results. With increasing MA, epsilon values of all matrix phases showed an increase whereas D values showed a decrease. In addition to that, lattice parameters a(Cu) and a(Ni) changed linearly with time, and a(Fe) displayed a slight decrease. The XRD peak belonging to the Cu (111) plane shifted towards larger 2-theta angles in the same direction. Contrary to Cu, the Fe (110) peak shifted to lower angles with MA time. However, the XRD peak belonging to the Ni (111) plane changed alternately. Similar results were obtained from both W-H plot analysis and the FPA calculations Minimum crystallite size and maximum internal strain rates were estimated for 8 h MA'ed Cu25WC, Fe25WC, and Ni25WC composite powders as 14.63 nm and 1.39%, 7.60 nm and 1.23%, and 17.65 nm and 1.13%, respectively. Transmission electron microscope observations were found in good agreement with the crystallite size of XRD calculations.