skip to main content

SciTech ConnectSciTech Connect

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

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 criticalmore » resolved shear stress has been approximated and the activation parameters of thermal strengthening of Ni{sub 3}Ge have been obtained.« less
Authors:
; ; ;  [1]
  1. Tomsk State University of Architecture and Building 2, Solyanaya Sq., Tomsk, 634003 (Russian Federation)
Publication Date:
OSTI Identifier:
22494421
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1698; Journal 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)
Country of Publication:
United States
Language:
English
Subject:
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