THERMAL STABILITY OF 3-DIMENSIONAL METALLIC GLASS Ni_(68)B_(21)Si_(11)

Under the isothermal and linear heating conditions respectively,the thermal sta-bility of 3-dimensional metallic glass Ni_(68)B_(21)Si_(11) produced by rapid quenching denucleated melt(RQDM)has been systematically studied by means of PE DSC7 differential scanningcalorimetry in the three influencing factors:denucleation of liquid alloy prior to rapidquenching,pre-anneal treatment of amorphous specimens,and cooling rate.The main contri-butions are represented by the following aspects.First,the thermal stability of metallic glassprepared by RQDM is obviously enhanced because of removal of pre-existing nuclei inadvance.This is substantiated by one of experimental data that the projected life of3-dimensional metallic glass Ni_(68)B_(21)Si_(11) is increased by an order of magnitude at 400K.Secondly,pre-anneal treatment of the amorphous alloy leads to a reduction of temperature foronset of crystallization,T_x,and crystallization heat,ΔH.Finally,quenching rates have little ef-fect on the thermal stability of amorphous alloys.