Untersuchung von Phasenumwandlungen in reinen Eisenlegierungen mit der magnetischen Waage

Abstract

Suszeptibilitätsmessungen an eisenreichen Zweistoff‐ und Dreistofflegierungen bei Temperaturen bis 1400 °C. Ermittlung der Grenzen des Zweiphasengebietes in den Systemen Eisen–Silizium, Eisen–Phosphor, Eisen–Titan, Eisen–Nickel und Eisen–Silizium–Kohlenstoff. Berechnung thermodynamischer Größen aus den ermittelten Phasengrenzen und Vergleich dieser Werte mit Angaben aus dem Schrifttum.

Experimental Study of High Temperature Phase Equilibria in the Iron-Rich Part of the Fe-P and Fe-C-P Systems

“…[23][24][25] The study of Roquet and Jegadan [23] is in agreement with the work of Lorenz et al [24] , whereas the present results correlate with the measurements of Fischer et al [25] . Although Lorenz et al [24] and Fischer et al [25] used the same experimental equipment, the maximum solubility of P in fcc and bcc differ from each other. The deviation can be assigned to the trace element levels of fcc stabilizing elements (C, Mn, N) in the samples produced.…”

“…Even small amounts of carbon increase the P solubility in fcc and will shift the gamma loop to higher amounts of P. As given in the supplementary Table S-I and Table S-III, alloys investigated in the present study show very low amounts of impurity elements. Similar chemical analysis was reported in the work of Fischer et al [25] (C £ 50 ppm, Si £ 50 ppm, Mn £ 10 ppm, S £ 50 ppm, N £ 40 ppm). Hence, these data sets [25] are considered as the most reliable for calculating solid state equilibrium between fcc and bcc.…”

“…[16][17][18][19][20][21][22] Solid phase equilibria in the fcc/bcc gamma loop region were studied in References 23 through 25; the maximum solubility of P in fcc was found to be 0.31 wt pct [24] or 0.265 wt pct [25] at 1150°C. Alloys with phosphorus content higher than 0.69 wt pct [24] or 0.59 wt pct, [25] respectively, do not show a bcc/fcc phase transformation in solid state. The solubility of P in bcc between 550°C and 1200°C was reported in References 26 through 29; a maximum value of 2.8 mass pct.…”

Assessment of the Fe-Ti system

“…The gamma loop has been investigated by Hellawell and Hume-Rothery, [21] Moll and Ogilvie, [24] Wada, [25] and Fisher et al [26] , yielding consistent results. The data are collected in Figure 6.…”

“…Fisher et al [26] used a magnetic balance to measure the magnetic susceptibility of 14 two-phase alloys produced by vacuum melting. The results were verified by dilatometric and metallographic investigations.…”