The Research On Preparation For Cu And Mo Intermetallics Via A Solid-Liquid Reaction Ball Milling Technique

Reaction ball milling process was selected to prepare intermetallic compound powders by reacting the medium with metal melt at a certain temperature range. In this paper Cu and Mo systems are selected to study. The identification of different phases is examined by X-ray diffraction, and the microstructure is analyzed by scanning electron microscopy and transmitting electron microscopy.Cu-Sn,Cu-Zn,Cu-Ni-Sn,Mo-Sn and Mo-Sb alloy systems were investigated by solid-liquid reaction milling with the ball-to-material mass ratio of 20:1 and the rotation rate of 80rpm, and mechanical alloying of Cu-Sn,Cu-Ni-Sn and Mo-Sb systems was carried out under similar conditions. The experimental results were enumerated as follows:(1)For the Cu-Sn alloy system, solid-state Cu6Sn5 and Sn powders were synthesized after milling the pure Sn melt for 6h at 573 K; A mixture of Cu6Sn5 and Cu3Sn was synthesized after milling for 12h at 673K; Cu3Sn was synthesized after milling for 12h at 773K; For the Cu-Zn alloy system, Cu5Zn8 was synthesized after milling the pure Zn melt for 4h, 8h and 12h at 723K; For the Cu-Ni-Sn ternary alloy system, only Cu6Sn5 powders were synthesized after milling the pure Sn melt by Cu balls and adding Ni powders at the same time or by Cu and Ni balls together for 12h and 24h at 573K. The SEM and TEM images of the as-milled products indicate that these powders were composed of agglomerated particles with a mean grain size of less than 100nm. A homogeneous and finer microstructure was obtained by adding the powders of Ni to the Cu-Sn system.(2)For the Mo-Sn and Mo-Sb binary alloy systems, MoSn2 powders were synthesized after milling the pure Sn melt for 6h at 573K; Mo3Sb7 powders were synthesized after milling the pure Sb melt for 6h at 993K, and a mixture of Mo3Sb7 and Mo powders were synthesized after milling for 36h at 993K respectively. The SEM and TEM images of the as-milled products indicate that these powders were composed of agglomerated particles with a mean grain size of less than 200nm.(3)For the Cu-Sn system, Cu6Sn5 was synthesized during long time milling in a planetary milling machine; For the Cu-Ni-Sn ternary system, after milling for 20h, the diffraction peaks of the Sn and Ni disappeared and the diffraction peaks of the Cu became wider ; For the Mo-Sb system, no intermetallics were prepared during 20 hours. After milling for 50 hours, the diffraction peaks of the Mo and Sb became wider and the diffraction intensity of Sb became weaken markedly.The mechanism, process and model of solid-liquid reaction milling for preparing intermetallics were discussed according to the experimental results above with a combination of the effects of liquid metals and mechanical force on solid metals. Also the differences between solid-liquid reaction milling and mechanical alloying were presented in this thesis.