Effect of ball milling time on microstructure and properties of nanocrystalline W-Cu composite powder

Nanocrystalline W-20%Cu(mass fraction) composite powder were fabricated by mechanical alloying(MA).The as-milled composite powder was characterized by XRD and SEM,respectively.The effect of milling time on the phase components,crystallite size,microstrain and morphology of the composites were studied,the mechanism of forming supersaturated solid solution during MA was also investigated.The results show that crystallite size and lattice parameter of W-Cu powder decrease with increasing ball milling time,whereas the mircostrain increase.When the powder was ball milled for 40 h,the average crystalline size of the W was about 22 nm;the solid solubility of Cu dissolved in W is largely extended after 40 h ball milling and the structure of the powder is nearly spherical.