Influence of the B and P content on the thermal stability and crystallization of cast iron based bulk amorphous alloys

The possibility of synthesizing bulk amorphous alloys with additions of B and P to commercial cast iron (Ci) of the chemical composition Fe81.5Si3.8C14Tm0.7 (at.%) was investigated. The effect of the B and P concentration on thermal stability, bulk glass forming ability (BGFA) and microstructure was studied by calorimetric (DSC and DTA) measurements as well as by X-ray diffraction. With the addition of 8.42 and 12.17 B to the commercial Ci bulk amorphous alloys with very wide supercooled liquid regions (77 and 81 K, respectively) could be produced. The partial replacement of Ci by B and P atoms increases the thermal stability and the BGFA. The kinetics of crystallization was investigated both by linear heating and by isothermal DSC measurements. The changes in the microstructure of the crystalline phases formed during linear heating were studied during further isothermal annealing at 833 K.