Deformation microstructure and positive temperature dependence of flow stress in Ni{sub 3}Ge

Journal Article · Fri Jan 15 00:00:00 EST 2016 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4937814· OSTI ID:22494421

Solov’eva, Yulia; Starenchenko, Vladimir; Starenchenko, Svetlana; Solov’ev, Artem ^[1]

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1. Tomsk State University of Architecture and Building 2, Solyanaya Sq., Tomsk, 634003 (Russian Federation)

Single crystalline specimens of Ni{sub 3}Ge were compressed along [0 0 1] at different temperatures. Temperature dependence of the critical resolved shear stress (τ{sub 0}(T)) has been obtained. Detailed measurements at cryogen temperatures (4.2-77 K temperature interval) showed that the increase of the yield stress with temperature starts at liquid helium temperature. The values of the apparent activation volume (V*) have been obtained as a result of stress relaxation tests repeated along the stress-strain curve at different stress levels at seven temperatures (77, 293, 373, 473, 573, 673, 773 K). Transmission electron microscopy (TEM) methods were used to analyze the evolution of dislocation structure with temperature and strain. The measurements of the straight dislocations fraction determined as δ = ρ{sub sd} / ρ, (ρ{sub sd} is the straight dislocation density, ρ is a total dislocation density) have been performed. The experimental data obtained in different tests in Ni{sub 3}Ge confirm two-stage nature of the positive temperature dependence of the flow stress of alloys with the L1{sub 2} structure. The model of thermal strengthening considering two different types of mechanisms, first acting at low temperatures and second at high has been proposed. Using this model the temperature dependence of the critical resolved shear stress has been approximated and the activation parameters of thermal strengthening of Ni{sub 3}Ge have been obtained.

• OSTI ID: 22494421
• Journal Information: AIP Conference Proceedings, Vol. 1698, Issue 1; Conference: AMTC-2015: 2. all-Russian scientific conference of young scientists on advanced materials in technology and construction, Tomsk (Russian Federation), 6-9 Oct 2015; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CRYOGENIC FLUIDS
DEFORMATION
DENSITY
DIAGRAMS
DISLOCATIONS
FLOW STRESS
GERMANIUM ALLOYS
HELIUM
LIQUEFIED GASES
MICROSTRUCTURE
MONOCRYSTALS
NICKEL ALLOYS
SHEAR
STRAINS
STRESS RELAXATION
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K
TRANSMISSION ELECTRON MICROSCOPY