Dynamic strain aging in a tungsten heavy metal

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Scripta Materialia

DOI:https://doi.org/10.1016/1359-6462(96)00262-X· OSTI ID:409677

Kumar, S; Pink, E ^[1]; Grill, R ^[2]

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1. Oesterreichische Akademie der Wissenschaften, Leoben (Austria). Erich-Schmid-Inst. fuer Festkoerperphysik
2. Technologie-Zentrum, Reutte (Austria). Plansee Aktiengesellschaft

Tungsten heavy metal is a mostly two-phase tungsten-base alloy containing spherical tungsten grains embedded in a f.c.c. binder. Good ductility (a low ductile-brittle transition temperature) is guaranteed in contrast to pure tungsten. As measures to improve the strength, solid-solution as well as precipitation hardening of the binder have been applied. It was the intention of this investigation to explore the possibilities for a strengthening method which has so far not been taken into consideration, namely exploiting the possible capacity of the material for dynamic strain aging (DSA). Such strengthening was proved to be technically feasible in steels. DSA and the accompanying effect of serrated flow (the Portevin-Le Chatelier effect) has never been reported to occur in tungsten heavy alloys. One recent observation of another aspect of DSA, i.e., of a negative strain-rate sensitivity, around 200 C is ambiguous for two reasons: (a) this low temperature cannot indicate an interstitial effect in tungsten--only perhaps in a b.c.c. iron-alloy binder, but not in a binder phase of common composition with a f.c.c. lattice; and (b) the fracture elongation showed a maximum at this temperature which is contrary to the idea of DSA. However, it is still to be expected that substitutional DSA may occur at higher temperatures due to tungsten which should be present in the binder phase after having been dissolved during liquid-phase sintering.

• OSTI ID: 409677
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 9 Vol. 35; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
FCC LATTICES
IRON ALLOYS
MICROSTRUCTURE
NICKEL ALLOYS
SAMPLE PREPARATION
SINTERING
STRAIN AGING
STRAIN RATE
STRAINS
STRESSES
TENSILE PROPERTIES
TUNGSTEN BASE ALLOYS