Stability of the β-Mn structure in rapidly quenched Fe–Mo–Cr–C alloys at high temperatures

Abstract

High-temperature x-ray diffraction (HT-XRD) is used to study the evolution of phase states of arcmelted and spinning 51.9Fe11.1Mo26.3Cr10.7C (at.%) alloys in the temperature range 293-1573 K. It is established that α-and β-Mn-like phases (χ and π, respectively) and solid solutions based on α-and γ-Fe identified by HT-XRD in the temperature range 293-978 K are metastable. A diffusion-free method for mutual transformations of Mn-like phases in the temperature range 873-978 K is proposed. It is shown that increase in temperature in HT-XRD conditions stabilizes metastable Mn-like phases. It is experimentally established, for the first time, that a stable β-Mn-like phase exists near the solidus in the Fe-Mo-Cr-C system. It is concluded that congruent crystallization is a way of forming a stable π-phase of composition Fe 5 MoCr 2.5 C. It is found out that a stable χ-phase and equilibria with its participation, α + η + M 23 C 6 + χ and χ + α + π + L, exist in the temperature range 1473-1523 K in the Fe-Mo-Cr-C system. It is determined that decomposition and/or mutual transformations of metastable Mn-like phases in 51.9Fe11.1Mo26.3Cr10.7C alloys occur at T ≈ 978 K, which is close to the temperature of α-Mn ⇔ β-Mn polymorphic transformation in pure manganese.

Effects of Heat Treatment on Microstructure and Magnetic Properties of Fe80Zr10B10 Alloy

“…Crystallization of Fe-based amorphous alloys has been an important research topic that has been extensively investigated over the past several decades. Different types of metastable crystallization phases are formed during primary crystallization, such as Fe 23 B 6 type [6][7][8][9][10][11], α-Mn type (χ) [12][13][14][15][16], cubic quasiperiodic (CQ) [17], Fe 12 Si 2 ZrB type [18,19], and β-Mn type phases [20][21][22]. FeZrB system alloys represent an important research direction for Febased alloys, and the crystallization phases of FeZrB alloys have been reported in several studies [23][24][25][26][27][28][29][30].…”