FORMATION, SOLID-SOLUTION HARDENING AND SOFTENING OF NANOCRYSTALLINE SOLID-SOLUTIONS PREPARED BY MECHANICAL ATTRITION

Nanocrystalline Ti100-xCux(x = 0-8), Nb100-xCux(x = 0-20), Ni100-xCux (x = 0-50), Cr100-xCux(x=0-20), Fe100-xCux(x=0-15). Cu100-xNix(x=0-50) , Cu100-xFex(x=0-50) and Cu100-xCox(x=0-50) solid solutions have been prepared by mechanical attrition of elemental powder mixtures. X-ray d iffraction, differential scanning calorimetry, and microhardness measu rements are utilized to investigate the structural evolution and the t hermal and mechanical properties of the solid solutions. The strength of the nanocrystalline solid solution depends on both solid solution h ardening and grain boundary hardening while the latter makes the major contribution to the total strength. The increase or decrease in hardn ess is dependent on the combined effects of solid solution hardening a nd either increased or decreased hardness resulting from changes in gr ain boundary hardening.