Microstructure, glass forming ability and magnetic properties of Nd₆₀Al₂₀Fe₂₀glass forming alloys

Abstract

Glass forming ability (GFA), magnetic properties and the microstructure of an Nd60Al20Fe20 as-cast rod were investigated in comparison with as-spun ribbons. The as-cast rod with a diameter of 3 mm and as-spun ribbons exhibit typical amorphous characters in x-ray diffraction patterns and distinct glass transition in differential scanning calorimetry traces. However, glass transition, crystallization behaviours and magnetic properties of an as-cast rod are different from that of as-spun ribbons. Microstructural investigations have revealed that a few nano-crystalline particles are embedded randomly in an amorphous matrix of the as-cast rod while the as-spun ribbons are fully amorphous. The formation of these nano-crystalline particles with a structure and composition similar to the Ax phase, as well as its effect on the magnetic properties and apparent GFA of Nd60Al20Fe20 glass forming alloys, were investigated.

Formation of Metastable Phases and Their Effect on the Glass-Forming Ability of Cu-Hf Binary Alloys

“…Of these, the empirical rules framed by Johnson 2) and Inoue et al 3) have played an important role in guiding the synthesis of multi-component BMGs in the past decade, but they appear not to be valid for designing binary BMGs. [10][11][12][13][14][15] Recently, we intensively studied the GFA of several binary alloy systems, and proposed a new parameter…”

“…is the forming enthalpy of their intermetallic counterparts) for the evaluation of the relationship between the alloy composition and the GFA of binary alloys from a thermodynamic point of view. [13][14][15] The parameter has proved useful in predicting the better glass former of several binary alloy systems. [13][14][15][16] However, the formation of intermediate metastable phases may dramatically influence the value of parameter à and the apparent GFA of alloys.…”

“…[13][14][15] The parameter has proved useful in predicting the better glass former of several binary alloy systems. [13][14][15][16] However, the formation of intermediate metastable phases may dramatically influence the value of parameter à and the apparent GFA of alloys. [13][14][15] Previous experimental results have shown that the intermediate metastable phases are easily precipitated from the supercooled liquid of glass-forming alloys upon rapid quenching, especially when the cooling rate is slightly lower than the critical cooling rate.…”

“…[13][14][15][16] However, the formation of intermediate metastable phases may dramatically influence the value of parameter à and the apparent GFA of alloys. [13][14][15] Previous experimental results have shown that the intermediate metastable phases are easily precipitated from the supercooled liquid of glass-forming alloys upon rapid quenching, especially when the cooling rate is slightly lower than the critical cooling rate. [17][18][19][20] In this work, the formation mechanism of metastable phases and their effect on the glass-forming ability of Cu-Hf binary alloys is investigated.…”

“…[13][14][15] Previous experimental results have shown that the intermediate metastable phases are easily precipitated from the supercooled liquid of glass-forming alloys upon rapid quenching, especially when the cooling rate is slightly lower than the critical cooling rate. [17][18][19][20] In this work, the formation mechanism of metastable phases and their effect on the glass-forming ability of Cu-Hf binary alloys is investigated. Taking the metastable phases into account, the parameter à is then revised to better predict the glass-forming ability of the alloys.…”