Pre-Primary Stage of Low Strain Rate Creep in Metals

Luboš Kloc; Václav Sklenička

doi:10.4028/www.scientific.net/MSF.604-605.351

Paper Titles

Study of Hot Formability of High Nitrogen Martensitic Stainless Steel
p.279

Failure at Elevated Temperatures: Influence of Dynamic Restoration
p.285

Long-Term Heat Treatments on Ti6Al4V-SiC_f Composite. Part I - Microstructural Characterization
p.331

Long-Term Heat Treatments on Ti6Al4V-SiC_f Composite. Part II - Mechanical Characterization
p.341

Pre-Primary Stage of Low Strain Rate Creep in Metals
p.351

Constitutive Equations in Creep of the AE44 Magnesium Alloy
p.357

Creep Response and Microstructural Changes during Intermittent Heating of Advanced Tempered Martensitic 9-12%Cr Steels
p.367

Warm Formability of AZ31 Magnesium Alloy Sheets under Different Process Conditions
p.379

Role of Boundaries in Control of Deformation Rate and Strength of Crystalline Materials
p.391

HomeMaterials Science ForumMaterials Science Forum Vols. 604-605Pre-Primary Stage of Low Strain Rate Creep in...

Pre-Primary Stage of Low Strain Rate Creep in Metals

Abstract:

Primarystageofcreepprocessisaperiodwhenthecreeprateisdecreasingduetomi-crostructuredevelopment.Thedislocationdensityevolvestothedynamicequilibriumvaluerelatedtotheappliedstress.Inlow-strainratecreepexperiments,similarstageofdecreasingstrainrateisobservedalongwithapparenttransitiontosteadystate.Nevertheless,deeperanalysisofthevariousparametersofthestageshowsthatthesubstanceoftheprocessmustbedifferent.Themainreasonsare:i)thestrainistoosmallfordislocationsubstructurerearrangement,ii)stressandtemperaturedependenciesofthetransitionstrainandrelaxationtimeoftheprocessdoesnotcorrespondtoanyoftheknownprimarycreepprocesses,iii)thestrainreachedduringthestageisalmostfullyrecoverable,sothatthedeformationisratheranelasticthanplasticone.Thetransitionstrainobservedinlowstrainrateexperimentsthusshouldbetreatedasaspecial“pre-primary”stage,whiletheapparentsecondary(steadystate)stageisinfactpartoftheprimarycreepstage.