The Synthesis, Structure And Properties Clarifying Of Pseudo High-entropy Type Metallic Glass

The effect of multicomponent on the formation,thermal stability and corrosion behavior of late transition metal base?Fe,Co,Ni?_86-87B_13-14 and?Fe,Co,Ni,Cr?_86-87B_13-14 amorphous alloys with low B contents less than 14 at%was examined with the aim of developing a new type of nanostructured late transition metal-based alloys with useful engineering properties in this paper.The Cr-containing alloys of?Fe,Co,Ni,Cr?₈₇B₁₃ and?Fe,Co,Ni,Cr?₈₆B₁₄ are composed of an amorphous phase.The amorphous phase in the?Fe,Co,Ni,Cr?₈₆B₁₄ alloy crystallizes through three stages where the first stage is due to the precipitation of fcc phase.The nanogranular fcc alloys exhibit high Vickers hardness of 1050 for the 14%B alloy and good corrosion resistance in H₂SO₄ and NaCl solutions which is comparable to the amorphous phase.In addition,the remaining amorphous phase in coexistent with nanoscale fcc phase was found to have high thermal stability to crystallization.The multicomponent design in late transition metal-B system leads to the synthesis of the mixed phase alloys consisting of nanoscale fcc phase embedded in the highly stable remaining amorphous phase in conjunction with high hardness and high corrosion resistance.We also examined high entropy effect on the formation,structure,thermal stability,mechanical properties and corrosion behavior for?Fe,Co,Ni,Cr?_100-xB_x?x=18-26 at%?in this paper.The as-quenched structure consists of an amorphous single phase for the 18-22 at%B alloy,and amorphous+tetragonal Cr₅B₃ phases for the 24-26 at%B alloy.All the as-spun high entropy alloy ribbons exhibit good bending ductility.The crystallization temperature?T_x?and Vickers hardness?H_v?increase with increasing B content,show maximum values of 803 K and 1130,respectively,at 22 at%B and then decreases to 793 K and 1070,respectively at 26at%B.The corrosion resistance in 3.5 mass%NaCl,0.1mol/L H₂SO₄ and 0.1mol/L HCl solutions evaluated by potential and anode current density is much better for the high entropy alloys as compared with the Fe-B alloys.The fully crystallized structure consists of fcc+FeB+Fe₂B+Cr₅B₃ phase for the high entropy 22-26 at%B alloys and bcc-Fe+Fe₂B for the Fe-B alloys.The significant improvement of the fundamental properties caused by the high entropy component modification is presumably due to the formation of Cr-B pair with higher B-rich components.Finally,we examine the enthalpy relaxation behavior of high entropy?Fe,Co,Ni,Cr?_100-xB_x?x=14-22 at%?amorphous alloys subjected to annealing at different temperatures for various periods.Furthermore,in the study,we have found that distinct annealing-induced enthalpy relaxation occurs even in the remaining amorphous phase containing nanoscale precipitation particles.The reason for the appearance of such a phenomenon is on the basis of the inhomogeneity in the amorphous structure.