Structural Characteristic and Crystallization Behavior of the (Fe_0.33Co_0.33Ni_0.33)_84- xCr₈Mn₈B_x High-Entropy-Amorphous Alloy Ribbons

The high-entropy-amorphous alloy (also called a pseudo-high-entropy alloy), as one of the categories of high-entropy alloys, is being developed as a new type of functional and structural high-strength material due to its advantages of high entropy and amorphousness. To further develop a new high-entropy-amorphous alloy, based on the results of previous studies, (Fe0.33Co0.33Ni0.33)(84 - x)Cr8Mn8Bx (x = 10-18, atomic fraction, %) alloys were synthesized (hereafter, alloys 10B, 11B, 13B, 15B, and 18B). The ribbons with a thickness of 20-30 mu m and a width of about 1.5 mm were produced by single-roller meltspinning. The alloy ribbons were annealed at different temperatures and then characterized by XRD, DSC, TEM, SEM, OM, universal tensile testing machine, and Vickers hardness tester. The results show that the addition of B improves the glass-forming ability and thermal stability of these alloys. The ribbons are fully amorphous at the low B content of 11%. Two exotherms were observed based on the DSC curves for the 11B-18B as-spun ribbons. The crystallization behaviors of 11B-18B alloy ribbons are as follows during heating: 11B and 13B, [am]->[ am' + bcc]->[am '' + bcc + fcc]->[ bcc + fcc + M23B6]->[fcc + M23B6]; 15B, [am]->[am' + fcc + bcc]->[am '' + bcc + fcc + M23B6]->[bcc + fcc + M23B6]->[fcc+ M23B6]; and 18B, [am]->[am' + fcc]->[am '' + fcc + M23B6]->[ fcc + M23B6] (The am' and am '' are the residual amorphous phases after the first and the second exotherms, respectively)