Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
PHASE-TRANSFORMATION IN FE-MO-C AND FE-W-C STEELS .1. THE STRUCTURAL EVOLUTION DURING TEMPERING AT 700-DEGREES-C
Autore:
SHTANSKY DV; INDEN G;
Indirizzi:
MAX PLANCK INST EISENFORSCH GMBH D-40074 DUSSELDORF GERMANY
Titolo Testata:
Acta materialia
fascicolo: 7, volume: 45, anno: 1997,
pagine: 2861 - 2878
SICI:
1359-6454(1997)45:7<2861:PIFAFS>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
THERMODYNAMIC EVALUATION; SYSTEM; CARBON; CONSTITUTION; EQUILIBRIA; ALLOYS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
D.V. Shtansky e G. Inden, "PHASE-TRANSFORMATION IN FE-MO-C AND FE-W-C STEELS .1. THE STRUCTURAL EVOLUTION DURING TEMPERING AT 700-DEGREES-C", Acta materialia, 45(7), 1997, pp. 2861-2878

Abstract

Mechanism and kinetics of carbide transformation during tempering at 700 degrees C have been studied in Fe-Mo-C and Fe-W-C steels (with up to 2.5% W or Mo) by transmission electron microscopy (TEM) and X-ray diffraction. The sequence of carbide formation is Fe3C-->Mo2C-->(Fe2MoC, M23C6) in molybdenum steels and Fe3C-->M6C-->M23C6 in tungsten steels. Increasing the alloying element level increases the rate of carbidereplacement reaction. In Fe-Mo-C steels the Fe2MoC carbides nucleate preferentially at the Fe3C-alpha interface and grow into cementite, whereas in Fe-W-C steels the M6C carbides usually precipitate inside cementite giving rise to the in situ transformation Fe3C-->M6C. The software DICTRA and THERMO-CALC were used to simulate cementite growth and to show the possibility of the in situ transformation. The M23C6 carbide is first confined to prior austenite grain boundaries and penetrates into the grains with increasing tempering time. During growth the M23C6 carbide absorbs surrounding pre-existing carbides. As a result, after tempering for 500 h, patches of two-phase areas with (M23C6 + alpha) or (M6C + alpha) are observed in tungsten steels, and patches of (M23C6 + alpha) or (Fe2MoC + alpha) in molybdenum steels. The alloying element partitioning between alpha and precipitated carbides was determined using TEM-EDS. It was established that the M23C6 carbide is stable at 700 degrees C in both investigated steels. The Fe2MoC carbide is stable in the Fe-Mo-C system at this temperature. The MC carbide was not observed even after tempering for 3000 h. (C) 1997 Acta Metallurgica Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 00:07:27