Non-isothermal crystallization behavior of Cr50Fe6Co7Mo14C15B6Y2 metallic glass with super high content of Cr and integrated merits

Abstract

In present work, non-isothermal crystallization behavior for novel Cr50Fe6Co7Mo14C15B6Y2 metallic glass (MG) with super high content of Cr and excellent merits was investigated by differential scanning calorimeter and X-ray diffraction. Both of the Kissinger and Ozawa methods show that the present glass transition is much harder than other transitions for a much larger apparent activation energy (E). While, the growth process of present second crystallization event is the easiest process, since it possesses the smallest E. Meanwhile, the local activation energy established by Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall methods both exhibit a trend of increasing to the maximum value at first and then gradual decrease until the finish of the crystallization, indicating that the difficulty increases until to the maximum at first and then gradually decreases during crystallization. Moreover, all the local Avrami exponent n(x) possesses a value of about 0 < n(x) < 1.5, implying a crystallization with pre-existing nuclei for present non-isothermal crystallization. Furthermore, the glass formation melt of present MG is considered as an intermediate one with moderate thermal stability. Additionally, the alloy firstly changes from monolithic MG to a composite of amorphous matrix superimposed with the main crystalline phases ((Fe,Cr)23(C,B)6, (Cr2.5Fe4.3Mo0.1)C3, Fe3Mo3C, FeC and some unknown phases), and then the remained amorphous matrix thoroughly changes to these crystalline phases with enriched crystal planes and fraction during crystallization. The results can supply basic data for designing valid crystallization strategy to tune performances of metallic glasses with high content of Cr.

Keywords

• Metallic glass with high content of Cr
• Non-isothermal crystallization behavior
• Avrami exponent
• Activation energy
• Kinetic fragility parameter