• Treffer 11 von 84
Zurück zur Trefferliste

Sub-critical crack growth in silicate glasses

  • Environmental conditions are known to influence sub-critical crack growth (SCCG) that are released from microscopic flaws at the glass surface, leading to stress corrosion phenomena at the crack tip. The processes at the crack-tip are complex and water has been identified as a key component governing SCCG at low crack velocities (region I). In particular, the influence of humidity accelerating crack propagation is well studied for industrial soda-lime silicate glasses, which are practically free (< 1000 ppm) of dissolved water. To shed light on the corrosion process, the situation at the crack-tip is reversed in the present study as dissolved water in larger fractions is present in the glass and crack propagation is triggered in dry environment. For this purpose, water-bearing silicate glasses of up to 8 wt% total water were synthesized in an internally heated pressure vessel at 0.5 GPa and compared to dry glasses of standard glass manufacturing. SCCG was measured using the doubleEnvironmental conditions are known to influence sub-critical crack growth (SCCG) that are released from microscopic flaws at the glass surface, leading to stress corrosion phenomena at the crack tip. The processes at the crack-tip are complex and water has been identified as a key component governing SCCG at low crack velocities (region I). In particular, the influence of humidity accelerating crack propagation is well studied for industrial soda-lime silicate glasses, which are practically free (< 1000 ppm) of dissolved water. To shed light on the corrosion process, the situation at the crack-tip is reversed in the present study as dissolved water in larger fractions is present in the glass and crack propagation is triggered in dry environment. For this purpose, water-bearing silicate glasses of up to 8 wt% total water were synthesized in an internally heated pressure vessel at 0.5 GPa and compared to dry glasses of standard glass manufacturing. SCCG was measured using the double cantilever beam technique and by Vickers indentation. For dry glasses, three trends in the crack growth velocity versus stress intensity curve were found. The slope in region I limited by environmental corrosion increases in the order sodium aluminosilicate < sodium borosilicate ≲ sodium lead silicate. The velocity range of region II reflecting the transition between corrosion affected and inert crack growth (region III), varies within one order of magnitude among the glasses. The KI region of inert crack growth strongly scatters between 0.4 and 0.9 MPam1/2. For hydrous glasses, it is found that those of low Tg are more prone to SCCG. As water strongly decreases Tg, it promotes SCCG. First results indicate that molecular water has a dominating influence on SCCG.zeige mehrzeige weniger

Volltext Dateien herunterladen

  • ICG_Waurischk_pub.pdf
    eng

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar
Metadaten
Autoren/innen:Tina Waurischk
Koautoren/innen:R. Balzer, P. Kiefer, Stefan Reinsch, Ralf Müller, H. Behrens, J. Deubener
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2018
Organisationseinheit der BAM:5 Werkstofftechnik
5 Werkstofftechnik / 5.6 Glas
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Freie Schlagwörter:Crack growth; DCB; Glass; Water speciation
Themenfelder/Aktivitätsfelder der BAM:Material
Material / Degradation von Werkstoffen und Materialien
Veranstaltung:ICG Annual Meeting 2018
Veranstaltungsort:Yokohama, Japan
Beginndatum der Veranstaltung:23.09.2018
Enddatum der Veranstaltung:26.09.2018
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:10.01.2019
Referierte Publikation:Nein