Different reaction mechanisms during mechanical alloying Ti50C50 and Ti33B67

Two different reaction mechanisms for Ti50C50 and Ti33B67 have been observed respectively during milling in a planetary ball mill. It is shown that a gradual reaction occurred during milling Ti50C50, while a self-sustained reaction was obtained during milling Ti33B67 under the same milling condition. Compared with the results of milling Ti50C50 in a spex mill, the difference in mechanism is suggested to be caused by the effect of plastic deformation on the changes of fine grains and internal strain during milling, and the different formation heat of TiC and TiB2, which is the driving force for the reactions. (C) 1996 American Institute of Physics.