Nb-W Alloy Prepared by Mechanical Alloying and Optimal Design of Corresponding Milling Variables

Abstract

The effects of milling variables on the particle sizes and purity of mechanically alloyed Nb-30W powders were quantitatively investigated using orthogonal test of three factors consisting of milling time A (12h, 24h and 48h), ball-to-powder ratio B (6:1, 10:1 and 20:1) and solid-to-liquid ratio C (1:0.2, 1:0.5 and 1:1) at three levels in order to optimize the milling variables of mechanically alloyed Nb-30W powders. Results indicated that the particle size was mainly determined by the solid-to-liquid ratio and the purity of powder was mainly affected by the ball-to-powder ratio and the milling time; best combination of all variables was found to be A2B2C1 with the particle size 12.62μm and Fe content 0.399%. After hot pressed, A2B2C1 combination obtained the highest mechanical properties. With the refining of particles during milling, the Fe contaminations of milled powder increased and were dissolved into Nb lattices to form Nb (Fe) solid solution; meanwhile, macro stress caused by plastic deformation of Nb particles was released.