Formation and structure-property correlation of new bulk Fe–B–Si–Hf metallic glasses

• Fe–B–Si–Hf metallic glasses are designed with a cluster-plus-glue-atom model.
• Bulk glassy rods with diameters 1.0–2.5 mm are reached at the model compositions.
• These glassy alloys exhibit high Bs (1.14–1.57 T) and low Hc (1.5–8.9 A/m).
• Fe72.5B16.67Si8.33Hf2.5 glassy alloys exhibit fracture strengths of ~ 4000 MPa with a plastic strain of 0.5%.
• A working local structure pattern is assigned to study the micro-alloying effect of the Fe–B–Si–Hf metallic glasses.

The present work is devoted to designing new Fe–B–Si–Hf multi-component bulk glassy alloys with good soft magnetic and mechanical properties, and also explored the structure-property correlation in the microalloyed Fe–B–Si amorphous alloy with Hf. Based on the cluster-plus-glue-atom model, a series of Fe–B–Si–Hf alloys with cluster formulas [Si–B2Fe8 − xHfx]Fe (x = 0–0.6) are produced. Our experiments show that a large glass-forming ability along with a critical glass formation size of 2.5 mm is reached at [Si–B2Fe7.7Hf0.3]Fe (in at.%: Fe72.5B16.7Si8.3Hf2.5). This glassy alloy shows a high fracture strength ~ 4000 MPa with a plastic strain of 0.5%, a high saturation magnetization ~ 1.45 T and a low coercive force ~ 1.5 A/m. The monotonic variations of the thermal glass stability, microhardness and the magnetic ordering parameters with the concentration of micro-alloying element Hf, the accessibility of calorimetric glass transition and the glass-forming ability of the Fe–B–Si–Hf glassy alloys are explained in terms of the intra- and inter-atomic cluster correlations in the amorphous structures.

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