Deformation of Earth Materials: Six Easy Pieces

Evans, Brian; Dresen, Georg

doi:10.1002/rog.1991.29.s2.823

Cited by 18 publications

(5 citation statements)

References 809 publications

(255 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Quantitative estimates of the viscosity of the Earth's lower crust and upper mantle are based on modeling of postseismic surface deformation [ Freed and Burgmann , 2004; Hetland and Hager , 2003; Hu et al , 2004; Kenner , 2004; Nishimura and Thatcher , 2003; Vergnolle et al , 2003] and extrapolation of laboratory measurements to natural conditions [e.g., Kohlstedt et al , 1995; Montesi and Hirth , 2003]. Early experimental investigations on natural samples revealed that so‐called “dry” or anhydrous rocks are much stronger than “wet” or hydrous aggregates, see reviews by Evans and Dresen [1991] and Evans and Kohlstedt [1995]. The terms “dry” and “wet” indicate mainly the heat treatment of samples before deformation, e.g., water‐added, as‐is or untreated, oven‐dried, or vacuum‐dried, but usually without specification of water content or the type of hydrogen incorporation, e.g., as fluid inclusions or structurally bonded hydrogen.…”

Section: Introductionmentioning

confidence: 99%

Influence of water fugacity and activation volume on the flow properties of fine‐grained anorthite aggregates

et al. 2006

View full text Add to dashboard Cite

[1] To specify quantitatively the effect of pressure and water weakening on the flow strength of feldspar we performed triaxial creep experiments in a gas deformation apparatus at temperatures of 1000-1150°C, confining pressures of 100-450 MPa, and axial stresses of 10-400 MPa, resulting in strain rates of $6 Â 10 À7 to 3 Â 10 À3 s À1 . Dense samples with a grain size of $3 mm were prepared by hot-isostatic pressing of anorthite glass powder. Hydrous samples contain about 0.33 ± 0.14 wt % H 2 O and dry specimens 0.0005-0.02 wt % H 2 O. The estimated residual glass content of wet samples is <2 vol %. Samples deformed by grain boundary diffusion-controlled creep at low stresses and dislocation creep at stresses^150 MPa. We estimate an activation volume of V % 24 cm 3 mol À1 for anhydrous samples deforming in diffusion creep. For wet samples, deformed in hydrous conditions with varying buffers fixing oxygen fugacity, the activation volume is about 38 cm 3 mol À1 . Creep rate of hydrous anorthite aggregates depends on water fugacity raised to a power of r = 1.0 ± 0.3, suggesting hydrolysis of oxygen bonds. Considering the effect of activation volume and water fugacity on extrapolation of constitutive laws to conditions prevailing in the continental lower crust, viscosities of hydrous feldspar aggregates increase by a factor of <3.Citation: Rybacki, E., M. Gottschalk, R. Wirth, and G. Dresen (2006), Influence of water fugacity and activation volume on the flow properties of fine-grained anorthite aggregates,

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of water fugacity and activation volume on the flow properties of fine‐grained anorthite aggregates

et al. 2006

View full text Add to dashboard Cite

show abstract

“…A common feature of many of the high-temperature constitutive laws is that creep rate is related to differential stress, (T, by a power law of the form, (15) where ai is the activity of the ith component, q,, n, and Qz are constants, and AZ is a weak function of T. Often experimentalists simply adopt (15) and determine n experimentally (Table 3) , the empirically determined flow law constants are, respectively, n=7.7 and 7.6 and Qx=255 and 420 kJ/mole (for deformation at strain rates of 10e3 to low6 s-' and temperatures of 500 to 1OOO'C). Thus, although there is general agreement concerning the stress exponent, activation energies for the two rocks differ significantly.…”

Section: Dislocation Creep Experimentsmentioning

confidence: 99%

Rheology of Rocks

Evans

Kohlstedt

2013

AGU Reference Shelf

Self Cite

116

View full text Add to dashboard Cite

For a rock of given mineralogy and microstructure, the variables important in determining strength are pressure, temperature, strain, strain history, strain rate, pore fluid pressure, grain size, fugacities of water and other volatiles, and chemical activities of the mineral components. Although earth scientists may now duplicate pressures and temperatures appropriate to the mantle and core in modern high pressure apparatus, they still cannot study mechanical properties under truly natural conditions. Time scales in the Earth are too long, and length scales too large. Since exact deformation conditions cannot be duplicated in the laboratory, the experimenter's strategy must involve determining the kinetic parameters of the appropriate processes at laboratory conditions and extrapolating to much lower strain rates [58]. Two convenient techniques are available to aid laboratory studies. Temperature and, hence, kinetic rates may be increased, or processes may be studied at smaller length scales [60]. Testing at high temperatures also imposes constraints. For example, maintaining chemical and phase stability and

show abstract

“…(1) 关键词主要集中在材料的力学性能方面，如 Brittle-Ductile Transition [7-13]、Mechanical Properties [14][15][16][17][18] 、 Deformation [19][20][21][22][23][24] 、 Fracture [25][26][27][28][29][30] 、 Toughness [31][32][33][34]、Strength [33,[35][36][37][38][39]、Brittle [40][41][42][43][44][45]、 Plasticity [46][47][48][49][50][51] [110,111]。磷元素是也钢中一种常见的微量元素，其含量一般在 0.005%~0.04%之间 [112,113] [122,125,126] [13] Murray G T. Brittle-Ductile Transition Temperatures in Ionic Crystals [J]. Journal of the American Ceramic Society, 1960, 43(6): 330-334.…”

unclassified

Research Progress on the Ductile-to-Brittle Transition of Metal Materials: The Impact of FATT50

Liu,

Tan

2024

mater

View full text Add to dashboard Cite

In low-temperature conditions, the ductile-to-brittle transition behavior of metal materials is crucial for the safety of engineering structures. This transition leads to the rapid expansion of cracks and could potentially result in accidents. Through retrieval and analysis of the Web of Science database, it was found that research on ductile brittle transition has shown a significant growth trend since 1990, with increasing international collaboration, primarily led by countries such as China, the United States, and Japan. Keyword analysis indicates a primary focus on aspects such as the mechanical properties of materials, the impact of composition on ductility and brittleness, microstructure, and temperature. This paper focuses on FATT50 (Fracture Appearance Transition Temperature at 50% Fracture Probability), 81 刘继江等：金属材料韧脆转变研究进展：FATT50 的影响 http://www.materialsrd.com comprehensively reviewing domestic and international standards for FATT50. It deeply analyzes the interrelationships between FATT50 and key factors such as material chemical composition, microstructure, and heat treatment. The study reveals that FATT50 is influenced by these factors collectively, especially in terms of chemical composition, microalloying elements, and impurities, which can significantly improve the low-temperature brittleness of metals and subsequently affecting the FATT50 temperature. Changes in microstructure may lead to increased brittleness of metals at low temperatures. Furthermore, the choice of heat treatment process also has a significant impact on FATT50, and adjustments in temperature and time can effectively improve or exacerbate the performance of metals at low temperatures. This research provides valuable insights for understanding and optimizing the performance of metal materials under low-temperature conditions, offering important guidance for engineering practices and materials design.

show abstract

Deformation of Earth Materials: Six Easy Pieces

Cited by 18 publications

References 809 publications

Influence of water fugacity and activation volume on the flow properties of fine‐grained anorthite aggregates

Influence of water fugacity and activation volume on the flow properties of fine‐grained anorthite aggregates

Rheology of Rocks

Research Progress on the Ductile-to-Brittle Transition of Metal Materials: The Impact of FATT50

Contact Info

Product

Resources

About