DIFFERENTIAL SCANNING CALORIMETRY STUDY OF VARIOUS INTERMETALLIC COMPOUNDS SUBJECTED TO MECHANICAL GRINDING

Two intermetallic compounds NiZr2 and Cu5Zn8 with good and poor glass-forming abilities, respectively, were subjected to mechanical grinding (MG) and the resulting structural changes have been studied by x-ray diffraction and DSC measurements. Similar analyses were also made for Cu30Ta70 powders subjected to mechanical alloying (MA), the system of which is known to possess a positive heat of formation. The total heat ΔHtot accumulated by the ball-milling, the heat ΔHx associated with the crystallization of an amorphous phase and the crystallization temperature Tx were deduced from the DSC spectra. We found that the behavior of ΔHtot, ΔHx and Tx plotted against ball-milling time is characteristic of the respective systems and can be discussed consistently in terms of the thermodynamic consideration. © 1990.