SOLID-STATE AMORPHIZATION TRANSFORMATIONS INDUCED BY MECHANICAL ALLOYING

The solid state amorphization transformations induced in the Fe-W, (Al or Ni)-(amorphous Fe-Si-B) and Ni-Ti systems were investigated by mec hanical alloying. The structure and characteristics of the mechanicall y alloyed materials were studied by X-ray diffraction, transmission el ectron microscopy, differential scanning calorimetry, differential the rmal analysis, and magnetic measurement. Amorphization by mechanical a lloying of the Fe-W system is attributed to a solid state amorphizatio n reaction in which lattice distortion induced by supersaturation of t ungsten in the iron crystal and a refinement of grain size may raise t he free energy of the iron crystal supersaturated by tungsten above th at of the amorphous phase. Amorphization by mechanical alloying of ele mental aluminum or nickel metal and amorphous Fe-Si-B alloy can also b e obtained within a composition range of the elemental metal. Differen t amorphization transformation paths are found in the Ni-Ti binary sys tem mechanically alloyed in argon, nitrogen and oxygen atmospheres res pectively.