Interfacial reaction-controlled reprecipitation of W atoms in liquid matrix phase during the sintering of W-8 pct Mo-7 pct Ni-3 pct Fe

Journal Article · Tue Dec 01 04:00:00 EST 1998 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-998-0195-x· OSTI ID:316025

Chan, T Y ^[1]; Lin, S T ^[2]

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1. Far-East Coll., Tainan (Taiwan, Province of China). Mechanical Engineering Dept.
2. National Taiwan Univ. of Science and Technology, Taipei (Taiwan, Province of China). Mechanical Engineering Dept.

Microstructural evolution and variation in phase composition of W-8 pct Mo-7 pct Ni-3 pct Fe alloy were investigated with respect to various isothermal holding times, ranging from 5 to 240 minutes, at a sintering temperature of 1480 C. Mass transfer was found to proceed actively in both the liquid matrix phase and the tungsten-based solid phase during the initial stage of the isothermal hold. Formation of large jagged grains was found to be a result of excessive interdiffusion between molybdenum and tungsten. The jagged grains gradually developed into spheroidal grains with the reprecipitation of supersaturated tungsten atoms in the liquid matrix phase, which also resulted in crystallization of the matrix phase with less lattice dilation during cooling. Based on model fitting, reprecipitation of tungsten atoms from the liquid matrix phase to grains is proposed to be controlled by a first-order interfacial reaction.

• Sponsoring Organization: USDOE
• OSTI ID: 316025
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 12 Vol. 29; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
INTERFACES
IRON ALLOYS
LIQUID METALS
MASS TRANSFER
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
PRECIPITATION
SINTERING
TUNGSTEN ALLOYS