51308
2020
eng
268
7
article
1
--
--
--
Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses
To explore the impact of ambient and structural water on static fatigue, the initiation and growth of 3279 Vickers induced median radial cracks were automatically recorded and analyzed. We find that humidity is more efficient in initiating cracks and promoting their growth than water, which is dissolved in the glass structure. In particular for slow crack growth (< 3x10-6 m s-1), tests in dry nitrogen showed a considerable decrease in the crack growth exponent with increasing water content of the glasses. On the other hand, if tests were performed in humid air, the crack growth exponent was independent of the water content of the hydrous glasses, while stress intensity decreased slightly. These observations indicate that water promotes the processes at the crack-tip regardless of its origin. However, ambient water is more efficient.
Frontiers in Materials
10.3389/fmats.2020.00268
urn:nbn:de:kobv:b43-513085
12.10.2020
Creative Commons - CC BY - Namensnennung 4.0 International
P. Kiefer
M. Maiwald
J. Deubener
R. Balzer
H. Behrens
Tina Waurischk
Stefan Reinsch
Ralf Müller
eng
uncontrolled
Indentation fracture toughness
eng
uncontrolled
Slow crack growth
eng
uncontrolled
Automated analysis
eng
uncontrolled
Hydrous glass
eng
uncontrolled
Vickers indentation
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Verlagsliteratur
Datei für die Öffentlichkeit verfügbar ("Open Access")
Wissenschaftliche Artikel der BAM
Bundesanstalt für Materialforschung und -prüfung (BAM)
https://opus4.kobv.de/opus4-bam/files/51308/2020kie-FM.pdf
50949
2020
eng
85
7
article
1
--
--
--
Water in Alkali Aluminosilicate Glasses
To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of <4 wt%, and molecular water becomes dominating at water content of >5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses.
frontiers in Materials
10.3389/fmats.2020.00085
urn:nbn:de:kobv:b43-509497
29.06.2020
false
true
Creative Commons - CC BY - Namensnennung 4.0 International
R. Balzer
H. Behrens
Tina Waurischk
Stefan Reinsch
Ralf Müller
P. Kiefer
J. Deubener
M. Fechtelkord
eng
uncontrolled
NMR spectroscopy
eng
uncontrolled
Alkali aluminosilicate glasses
eng
uncontrolled
Water speciation
eng
uncontrolled
Glass transition
eng
uncontrolled
Infrared spectroscopy
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Verlagsliteratur
Datei für die Öffentlichkeit verfügbar ("Open Access")
Wissenschaftliche Artikel der BAM
Bundesanstalt für Materialforschung und -prüfung (BAM)
https://opus4.kobv.de/opus4-bam/files/50949/2020 Balzer_Water in alumino silicate glasses.pdf
50682
2020
eng
Articel 66
7
article
1
--
--
--
Crack Growth in Hydrous Soda-Lime Silicate Glass
Stable crack growth was measured for nominal dry and water-bearing (6 wt%) soda-lime silicate glasses in double cantilever beam geometry and combined with DMA studies on the effects of dissolved water on internal friction and glass transition, respectively. In vacuum, a decreased slope of logarithmic crack growth velocity versus stress intensity factor is evident for the hydrous glass in line with an increase of b-relaxation intensity indicating more energy Dissipation during fracture. Further, inert crack growth in hydrous glass is found to be divided into sections of different slope, which indicates different water related crack propagation mechanism. In ambient air, a largely extended region II is observed for the hydrous glass, which indicates that crack growth is more sensitive to ambient water.
Frontiers in Materials
10.3389/fmats.2020.00066
urn:nbn:de:kobv:b43-506829
28.12.2020
Creative Commons - CC BY - Namensnennung 4.0 International
Tina Waurischk
Ralf Müller
Stefan Reinsch
P. Kiefer
J. Deubener
R. Balzer
H. Behrens
eng
uncontrolled
Internal friction
eng
uncontrolled
Soda-lime silicate glass
eng
uncontrolled
Water content
eng
uncontrolled
Stable crack growth
eng
uncontrolled
DCB geometry
eng
uncontrolled
Stress intensity factor
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Verlagsliteratur
Datei für die Öffentlichkeit verfügbar ("Open Access")
Wissenschaftliche Artikel der BAM
Bundesanstalt für Materialforschung und -prüfung (BAM)
https://opus4.kobv.de/opus4-bam/files/50682/2020 Waurischk Crack Growth in Hydrous Soda-Lime Silicate Glass.pdf
49537
2019
eng
lecture
0
--
--
--
Density, microhardness and elastic moduli of hydrous soda-lime silicate glasses
The effect of structural water on density, elastic constants and microhardness of water-bearing soda-lime-silica glasses of up to 21.5 mol% total water is studied.
25th International Congress on Glass (ICG2019)
Boston, MA, USA
09.06.2019
14.06.2019
false
true
0
P. Kiefer
eng
uncontrolled
Elastic constants
eng
uncontrolled
Soda-lime-silica glass
eng
uncontrolled
Water content
eng
uncontrolled
Microhardness
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
50393
2019
eng
119739
527
article
Elsevier B.V.
1
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--
--
Statistical analysis of propagation rates of indentation-induced radial cracks
Due to the stochastic nature of crack nucleation by Vickers indentation, a statistical analysis of propagation rates of 185 radial cracks was performed. Crack growth was observed directly using a video camera with high Image acquisition rate. It is found that propagation rates are controlled by the environmental reactions at the crack-tip shortly after their initiation (< 1 s). Calibration of the stress intensity KI showed that the residual stress factor χ and the exponent n of the equation KI==χPc−n (with P==load and c==crack length) are broadly distributed among the 185 analyzed cracks, ranging from 10−16 to 104 and from 0.1 to 5, respectively. For the most frequent crack, the equation KI==0.052Pc−1.47 holds. The results show that correlations of indentation-induced crack length to stress intensity necessitate the use of statistical significant data that are calibrated by the environmental reactions at the crack-tip.
Journal of Non-Crystalline Solids
10.1016/j.jnoncrysol.2019.119739
13.02.2020
false
true
P. Kiefer
J. Deubener
Ralf Müller
H. Behrens
eng
uncontrolled
Stress intensity factor
eng
uncontrolled
Vickers indentation
eng
uncontrolled
Subcritical crack growth
eng
uncontrolled
Soda-lime-silica glass
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")
48758
2019
eng
119480
521
article
Elsevier B.V.
1
--
--
--
Density, elastic constants and indentation hardness of hydrous soda-lime silica glasses
The effect of structural water on density, elastic constants and microhardness of water-bearing soda-lime-silica glasses of up to 21.5 mol% total water is studied. It is found that the Poisson ratio and the water content are positively correlated, while density and the elastic moduli decrease with increasing water content. Vickers hardness decreases by approximately 27% from the dry to the most hydrous glass. For water fractions <3 mol%, the dependencies are non-linear reflecting the non-linear change in the concentrations of OH and H2O molecules dissolved, whereas for water fractions >3 mol% linear dependencies are found. To distinguish the effect of structural water and environmental water, indentations were performed in toluene, nitrogen gas and air. Timedependent softening was evident for testing dry glasses in humid atmospheres as well as for tests of hydrous glasses in dry atmospheres. This indicates that the response times of dissolved water species are effectively equal in both scenarios.
Journal of Non-Crystalline Solids
10.1016/j.jnoncrysol.2019.119480
0022-3093
1873-4812
26.09.2019
P. Kiefer
R. Balzer
J. Deubener
H. Behrens
Tina Waurischk
Stefan Reinsch
Ralf Müller
eng
uncontrolled
Elastic constants
eng
uncontrolled
Soda-lime-silica
eng
uncontrolled
Glass
eng
uncontrolled
Water content
eng
uncontrolled
Microhardness
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")
48343
2019
eng
poster
0
--
--
--
Subcritical crack growth in water bearing soda-aluminosilicate glasses
The subcritical crack growth in water bearing soda-aluminosilicate glasses is compared to the crack growth in a commercial soda-lime silicate glass. The water speciation is shown for comparison of water species in the material. Differences will be discussed in the poster session.
Glastechnische Tagung 2019
Nürnberg, Germany
13.05.2019
15.05.2019
false
true
P. Kiefer
eng
uncontrolled
Glass
eng
uncontrolled
Crack growth
eng
uncontrolled
Vickers
eng
uncontrolled
Water speciation
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
45608
2018
eng
30
39
497
article
Elsevier B.V.
1
--
--
--
Structural relaxation mechanisms in hydrous sodium borosilicate glasses
Borosilicate glasses (16Na2O–10B2O3–74SiO2, NBS) with water contents up to 22 mol% H2O were prepared to study the effect of water on structural relaxation using DTA, viscometry and internal friction measurements. The results show that the glass transition temperature Tg of DTA and the isokom temperature T12, of viscometry are in excellent agreement, confirming the equivalence of enthalpy and viscous relaxation for NBS glass. Combining Tg data with water speciation data demonstrates that OH groups are mainly responsible for the decrease of Tg with increasing hydration, while molecular water plays only a minor role. Internal friction spectra at 7.125 Hz confirm the decisive influence of water on mechanical relaxation. The temperature range of α-relaxation (glass transition) strongly decreases while two β-relaxation peaks (sub-Tg) progressively appear with increasing water content. A high temperature β-relaxation peak, attributed to the presence of OH groups, shifts from 670 to 450 K as total water content increases from 0.01 to 5 wt%. A low temperature β-relaxation peak, attributed to molecular water, appears at 380 K and 330 K in glasses containing 3 and 5 wt% H2O, respectively. These findings suggest that relaxation mechanism of different hydrous species at low temperature may contribute to fatigue of stressed glasses.
Journal of Non-Crystalline Solids
10.1016/j.jnoncrysol.2018.05.025
30.07.2018
H. Behrens
U. Bauer
Stefan Reinsch
P. Kiefer
Ralf Müller
J. Deubener
eng
uncontrolled
Borosilicate glass
eng
uncontrolled
Water
eng
uncontrolled
Relaxation
eng
uncontrolled
Internal friction
eng
uncontrolled
Glass transition
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Verlagsliteratur
Datei im Netzwerk der BAM verfügbar ("Closed Access")
45703
2018
eng
poster
0
--
--
--
Statistical analysis of Vickers induced subcritical crack growth in soda-lime silicate glasses
Studies on Vickers induced subcritical crack growth are controversially discussed since the stresses that drive the crack growth are distributed three dimensionally within the material and cannot be retraced by available methods. Hence, empirical approaches are used to calculate mechanical material parameters such as the stress intensity factor KI. However, the results of these approaches show large deviations from those measured by standardized techniques such as double cantilever beam (DCB) or double cleavage drilled compression (DCDC). Yet, small specimen sizes and low specimen quantities can prevent the execution of DCB and DCDC measurements. Here we present an approach that is based on a statistical analysis of Vickers induced radial cracks. For this purpose more than 150 single radial cracks were analyzed. The cracks were generated in a commercial soda-lime silicate glass. The experiments were performed in a glovebox purged with dry nitrogen gas to minimize the influence of atmospheric water on crack growth. The temporally resolved evolution of the radial cracks was monitored in-situ using an inverted microscope equipped with a camera system directly below the Vickers indenter. An automated image analysis software was used to determine the crack length over time. The data show that the crack propagation and thereby the crack velocities are not uniformly but statistically distributed. These findings allow, using the statistical mean value of the distributions in combination with DCB data, a precise formulation of KI for each measured crack length.
92nd Annual Meeting of the German Society of Glass Technology in Conjunction with the Annual Meetings of the Czech Glass Society & the Slovak Glass Society
Bayreuth, Germany
28.05.2018
30.05.2018
P. Kiefer
eng
uncontrolled
Crack growth
eng
uncontrolled
Soda-lime silicate glass
eng
uncontrolled
Vickers
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
45704
2018
eng
poster
0
--
--
--
Subcritical crack growth in water bearing soda-lime silicate glasses
The presence of water in the surrounding atmosphere of a propagating crack has a major influence on the subcritical crack growth. While these external phenomena are well understood, there is still a lack of knowledge on the influence of structurally bound water on crack propagation. Thus, our recent study aims on the analysis of crack propagation in water bearing soda-lime silicate glasses with up to 8 wt.% water. The samples were synthesized in an internally heated pressure vessel at 0.5 GPa. Since this preparation route limits the sample sizes, standard test geometries allowing for the determination of stress intensity factors, such as double cantilever beam, are not feasible. Thus, radial cracks in the hydrous glasses were initiated by Vickers indentation and crack growth was simultaneously captured with a camera system. An automated image analysis algorithm was used for the analysis of the crack length of each single video frame. To minimize influences by atmospheric water, all experiments were conducted in a glovebox purged with dry N2. About 150 cracks per glass composition were analyzed to provide statistical significance of the Vickers-induced SCCG. The results show that structurally bound water has a major influence on SCCG by means of crack lengths, growth rates and time of crack initiation.
92nd Annual Meeting of the German Society of Glass Technology in Conjunction with the Annual Meetings of the Czech Glass Society & the Slovak Glass Society
Bayreuth, Germany
28.05.2018
30.05.2018
P. Kiefer
eng
uncontrolled
Water speciation
eng
uncontrolled
Soda-lime silicate glass
eng
uncontrolled
Crack growth
eng
uncontrolled
Vickers
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
45707
2018
eng
lecture
0
--
--
--
Statistical analysis of subcritical crack growth in water bearing soda-lime silicate glasses
The talk was given at the PNCS-ESG 2018 in Saint Malo and summarizes the actual findings about Vickers induced crack growth in water bearing soda-lime silicate glasses.
15th International Conference on the Physics of Non-Crystalline Solids & 14th European Society of Glass Conference
Saint Malo, France
09.07.2018
13.07.2018
0
P. Kiefer
eng
uncontrolled
Water speciation
eng
uncontrolled
Vickers
eng
uncontrolled
Crack growth
eng
uncontrolled
Soda-lime silicate glass
Ingenieurwissenschaften und zugeordnete Tätigkeiten
5 Werkstofftechnik
5.6 Glas
Material
Degradation von Werkstoffen
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
44211
2017
eng
lecture
0
--
--
--
In-situ observation of sub-critical crack growth in water bearing borate glasses
185 cracks were initiated in a soda-lime-silica glass by Vickers indentation and grown under controlled dry nitrogen atmosphere. Direct observation of subcritical crack growth (SCCG) upon indentation was performed using a video camera with an image acquisition rate of 3 ms. The results show that the validity of K(c) relations used to determine the indentation fracture toughness from a single imprint is questionable. It seems that correlation of crack length to stress intensity necessitate the use of statistical significant data of multiple crack events.
FFAG 7: 7th International Workshop on Flow and Fracture of Advanced Glasses
Aalborg, Denmark
02.07.2017
05.07.2017
0
P. Kiefer
eng
uncontrolled
Sub critical crack growth
eng
uncontrolled
Glass
eng
uncontrolled
Vickers
eng
uncontrolled
Water bearing glass
eng
uncontrolled
Indentation fracture toughness
Ingenieurwissenschaften und zugeordnete Tätigkeiten
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
44215
2017
deu
lecture
0
--
--
--
In-situ Beobachtung und statistische Analyse des unterkritischen Risswachstums in Gläsern
Um das Risswachstum in Gläsern zu untersuchen, sind in einer Glovebox 185 Risse ausgehen von Vickers-Eindrücken in Kalk-Natron-Glas initiiert und gewachsen. Die direkte Beobachtung des unterkritischen Risswachstums erfolgte mit einer Hochgeschwindigkeitskamera. Die Ergebnisse zeigen, dass die statistische Auswertung vieler radialer Risse von multiplen Rissevents notwendig ist, um eine Korrelation zum Spannungsintensitätsfaktor ziehen zu können.
Fachausschuss I der Deutschen Glastechnischen Gesellschaft (DGG)
Erlangen, Germany
26.09.2017
0
P. Kiefer
deu
uncontrolled
Risswachstum
deu
uncontrolled
Glas
deu
uncontrolled
Vickers
deu
uncontrolled
In-situ
Ingenieurwissenschaften und zugeordnete Tätigkeiten
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation
40812
2017
eng
lecture
0
--
--
--
Viscosity of water bearing glasses in the glass transition range – Phosphates vs. silicates and borates
Water has a strong impact on the viscosity and the transition temperature of oxide glasses. It acts as a fluxing agent, reducing viscosity particularly in the glass transition range, and by that flattening the viscosity-temperature curve and decreasing the fragility of hydrous glass melts. This general behavior is found for silicate and borate as well as in borosilicate compositions. However, there is still a lack of data with respect to hydrous phosphate glasses. Here, we study the influence of structural water on the viscosity of Li2O-MgO-(Al2O3-)P2O5 glasses. The glasses were synthesized in an internally heated pressure vessel (IHPV) at a pressure of 0.5 GPa. The selected pressure allows for the synthesis of glass specimens with water contents of several wt.%. The viscosity measurements were carried out in the glass transition range, i.e. log η ≈ 10-13 (η in Pa s), using a sphere penetration viscometer. The measured data agree with glass transition temperatures measured by differential thermo analysis. First results further suggest that the fragility of the analyzed phosphates decreases with increasing water content.
91. Glastechnische Tagung
Weimar, Germany
28.05.2017
31.05.2017
0
P. Kiefer
eng
uncontrolled
Water-bearing glasses
eng
uncontrolled
Viscosity
Angewandte Physik
Datei im Netzwerk der BAM verfügbar ("Closed Access")
Präsentation