Mechanical and chemical effects of Mo powder in the milling process

摘要

Using a laser particle size analyzer, X-ray diffraction (XRD) and scanning electron microscopy (SEM) and other analytical instruments to study the pure Mo powder particle size, grain size and microstructure of strain variation changing in the mechanical milling process with milling time.The microstructure characteristics and refinement mechanism of pure Mo powder during wet milling were also discussed.Mo powder grain size refinement is obvious at the beginning of ball milling and then becomes stable after 20h ball milling.After 30h ball milling, Superfine Mo powder with average grain size to 17.9 nm and average particle size to 1.371 μm.Particle size distribution curve appears as bimodal characteristics of nano, sub-micron and micron sambong coexistence region.The grain size and micro-strain appear relationship of ε =12.268D-1.229.The mechanism of refinement particles is that Mo powder produces a strong initial plastic deformation, at the beginning of ball milling, defect density dramatic increase in the occurrence of a strong work hardening powder, powder accelerated fragmentation;after 20h ball milling, fragmentation and cold welding reach dynamic equilibrium, powder particle size tends to be stable.