Effect Of Several Trace Elements On The Glass Forming Ability And Mechanical Properties Of Fe-Cr-Zr-B-Mo

Fe-based bulk metallic glasses（Fe-BMGs）have attracted much attention due to their excellent soft magnetic properties,mechanical properties,corrosion resistance and low material cost.Compared with boron steel,Fe-BMGs can hold more than 18 at.%of B atoms,which makes it a good choice for nuclear power plants to absorb spent fuel neutrons.It is found that excessive B content will deteriorate the glass forming ability（GFA）of the alloy,so the composition of Fe₅₇Cr₁₀Zr₈B₁₈Mo₇BMGs with 18 at.%B content is selected.By changing the content of Nb,Mo,Zr and adding 1 at.%Si,Cu,Al to adjust the composition,and by using scanning electron microscopy（SEM）,X-ray diffraction（XRD）,differential scanning calorimetry（DSC）and universal mechanical testing machine to study the microstructure evolution rule,GFA,thermal stability and mechanical properties.The main results are as follows:The GFA of the Fe₅₇Cr₁₀Zr₈B₁₈Mo_7-xNb_x（x=1-5）alloy reaches the maximum at x=2 and 3,the critical diameter is 3 mm.The corresponding supercooled liquid region widths（ΔT_x）are 78K and 71 K,respectively,the compressive strength and Vickers hardness are 1950 MPa,1310H_Vand 2062 MPa,1180 H_V,respectively.Compared to x=3,the x=2 alloy with a diameter of 3mm has a completely featureless amorphous structure.The replacement of Mo by 2 at.%Nb is helpful to improve the GFA of Fe₅₇Cr₁₀Zr₈B₁₈Mo₇alloy.Compared with 1 at.%Zr replacing Mo,2 at.%Mo replacing Cr makes Fe₅₇Cr₈Zr₈B₁₈Mo₇Nb₂and Fe₅₇Cr₁₀Zr₈B₁₈Mo₅Nb₂have the same GFA.The addition of 1at.%Al,Cu and Si will deteriorate the GFA of Fe₅₇Cr₁₀Zr₈B₁₈Mo₅Nb₂,and the deterioration degree of Al is the greatest.