2004
Simulation of structural stability of weld joints of heat-resistant steels.
SOPOUŠEK, Jiří, Rudolf FORET a Bronislav ZLÁMALZákladní údaje
Originální název
Simulation of structural stability of weld joints of heat-resistant steels.
Název česky
Simulace strukturní stability svarových spojů žárovzdorných ocelí.
Autoři
SOPOUŠEK, Jiří (203 Česká republika, garant), Rudolf FORET (203 Česká republika) a Bronislav ZLÁMAL (203 Česká republika)
Vydání
Vienna, Thermodynamics of Alloys TOFA 2004, od s. P28, 1 s. 2004
Nakladatel
Dept. of Inorganic Chemistry, Materials Chemistry Group, Univ. of Vienna & Austrian Chemical Society
Další údaje
Jazyk
angličtina
Typ výsledku
Stať ve sborníku
Obor
10403 Physical chemistry
Stát vydavatele
Rakousko
Utajení
není předmětem státního či obchodního tajemství
Kód RIV
RIV/00216224:14310/04:00011568
Organizační jednotka
Přírodovědecká fakulta
Klíčová slova anglicky
DICTRA;phase;diffusion;CALPHAD
Změněno: 20. 9. 2004 13:00, prof. RNDr. Jiří Sopoušek, CSc.
V originále
Knowledge of microstructure stabilities is essential for reliable estimations of the lifetime limitations of materials and welded joints at higher temperatures. This information may be deduced from material phase diagrams and from heterogeneous weld joint simulations. The phase diagrams can be calculated using CALPHAD method [1]. This method complemented with appropriate diffusion approach [2], [3] can help us to simulate phase and element profile evolutions inside diffusion-affected zone of weld joint too. Thermodynamic database STEEL [4] and kinetic database DIF mentioned in [5] are used. The weld joints are simulated as heterogeneous diffusion couples. The results of the equilibrium calculations are presented as the phase diagram cross-sections of the selected materials: heat resistant steels and weld metals. The same equilibrium calculations offer element activities too. The carbon activity temperature dependences were calculated for individual materials. The observed difference between the carbon activities of two different materials (at given temperature) enabled us to predict diffusion flow direction, which can be in some cases opposite then deduced from carbon contents in some steel combinations (carbon up-hill diffusion). The simulations respect the coexistence of different carbide phases in the materials and they are conducted on the assumption that under the examined conditions the local phase equilibrium holds and that diffusion is the control process of phase transformation. The phase diagram calculations and diffusion couple simulations involving time-distance dependences for phase and element redistributions in diffusion-affected zones enabled us to obtain a basic information, which allow to estimate thermodynamic and diffusion stabilities of the studied materials and their weld joints and finally to deduce the weakest point(s) of the weld joins.
Česky
Jsou vypočteny fázové diagramy metodou CALPHAD method za použití vytvořené termodynamické a kinetické databáze. Svarové spoje jsou simulovány jako difúzní páry. Z fázových a chemických simulovaných profilů je usuzováno na mikrostrukturu a mechanickou stabilitu spojení.
Návaznosti
GA106/03/0636, projekt VaV |
|