The Characteristic Grain Size and the Compressive Strength of Ice Containing a Bimodal Distribution of Grain Sizes

1989 ◽  
Vol 111 (1) ◽  
pp. 61-62
Author(s):  
E. M. Schulson ◽  
J. L. Laughlin
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Grain Refinement ◽  
Bimodal Distribution ◽  
Grain Sizes ◽  
Freshwater Ice ◽  
Polycrystalline Ice

The purpose of this communication is to show through experiment that the compressive strength of polycrystalline ice, which contains a bimodal distribution of grain sizes, can be expressed in terms of a characteristic grain size. The work was performed in response to an awareness that grain refinement strengthens both columnar [1] and granular [2] freshwater ice deformed under compression, and that ice formed naturally often contains grains of more than one size. A detailed discussion is given elsewhere [3].

The Fracture Toughness of Ice Over a Range of Grain Sizes

1988 ◽  
Vol 110 (2) ◽  
pp. 192-196 ◽  
Author(s):  
W. A. Nixon ◽  
E. M. Schulson
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Research Laboratory ◽  
Circular Cylinders ◽  
Notched Specimen ◽  
Grain Sizes ◽  
Freshwater Ice ◽  
Thayer School ◽  
Percent Decrease

Tests have been performed at −10°C on circumferentially notched right circular cylinders of randomly oriented granular polycrystalline freshwater ice, to determine whether grain size affects fracture toughness (KIc). Grain sizes, as measured by the linear intercept method, varied from 1.6 mm to 9.3 mm in diameter. The circumferentially notched specimen was used because of the ease with which it can be manufactured from right circular cylinders, made regularly and with considerable accuracy of alignment for some years now by workers of the Thayer School Ice Research Laboratory. A slight (25 percent) decrease in values of KIc is observed as grain size increases over the range investigated. Consideration is given to the cause of this effect and to its possible contribution to the scatter in KIc values observed by earlier workers. Other possible causes of this scatter are indicated.

scholarly journals Characterization of mechanical properties of barium titanate ceramics with different grain sizes

2018 ◽  
Vol 36 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Tomasz Trzepiecinski ◽  
Magdalena Gromada
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Barium Titanate ◽  
Testing Machine ◽  
Compression Tests ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Uniaxial Testing ◽  
Different Grain Size ◽  
Titanate Ceramics

AbstractIn this paper, three BaTiO3 powders of various particle size distributions were obtained as a result of mechanical activation in the mixer mill. Green barium titanate pellets and cylindrical specimens were fabricated by both uniaxial and isostatic pressing methods. As a result of the application of different maximal sintering temperatures, the obtained materials were characterized by various average grain sizes: 0.8 μm, 20 μm and 31.0 μm. The basic properties of sintered pellets and cylinders were determined and the influence of materials average grain size on their Young’s modulus and compressive strength were determined through compression tests in a uniaxial testing machine, Zwick/Roell Z100. The elastic properties were similar for tested materials with a different grain size. However, the microstructure of BaTiO3 strongly influenced the compressive strength.

scholarly journals Microstructure Development in Additive Friction Stir-Deposited Cu

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1538
Author(s):  
Jonathan L. Priedeman ◽  
Brandon J. Phillips ◽  
Jessica J. Lopez ◽  
Brett E. Tucker Roper ◽  
B. Chad Hornbuckle ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Microstructure Evolution ◽  
Vickers Hardness ◽  
Work Hardening ◽  
Surface Oxide ◽  
Microstructure Development ◽  
Friction Stir ◽  
Grain Sizes

This work details the additive friction stir-deposition (AFS-D) of copper and evaluation of its microstructure evolution and hardness. During deposition, a surface oxide is formed on the deposit exterior. A very fine porosity is formed at the substrate–deposit interface. The deposit (four layers of 1 mm nominal height) is otherwise fully dense. The grains appear to have recrystallized throughout the deposit with varying levels of refinement. The prevalence of twinning was found to be dependent upon the grain size, with larger local grain sizes having a higher number of twins. Vickers hardness measurements reveal that the deposit is softer than the starting feedstock. This result indicates that grain refinement and/or higher twin densities do not replace work hardening contributions to strengthen Cu processed by additive friction stir-deposition.

scholarly journals The Tensile Strength of Polycrystalline Ice (Abstract only)

1983 ◽  
Vol 4 ◽  
pp. 305
Author(s):  
E. M. Schulson ◽  
J. H. Currier
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Functional Relationship ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Structure Property ◽  
Property A ◽  
Freshwater Ice ◽  
Polycrystalline Ice ◽  
Image Position

Structure/property relationships, while well-researched in metallic and in some ceramic materials, have been essentially ignored 1n studies on the mechanical properties of ice. To rectify this situation, experiments have been designed and have been underway for the past two years to investigate one mechanical property, i.e. tensile strength, and the effect of one structural feature, i.e. grain size, on this property. A clear relationship has been established, and is reported here. Other work is in progress and will also be reported in due course. Equiaxed and randomly oriented aggregates of freshwater ice, of grain size (as seen in two-dimensional sections) varying from 1.0 to 7.3 mm, were prepared in the form of large cylinders (91 mm diameter × 231 mm length). The aggregates were deformed to fracture under uniaxial tension, using a specially designed ball-joint and yoke assembly to ensure axial loading. Data were obtained at -10 ±0.2°C (i.e. at 96% of the melting point) at a strain-rate of 10−6 s−1. Figure 1 shows that the tensile strength decreases with increasing grain size, from 1.25 MPa for d = 1 mm to 0.80 MPa for d = 7 mm. Moreover, this figure illustrates that the data are highly reproducible; i.e. that strength is reproducible to within ±5% for a given grain size over the complete range. Fig. 1. Graph showing the decrease in the tensile strength of ice with increasing grain size. Concerning the functional relationship between tensile strength of and grain size, analysis shows that the following equation is well obeyed: Where σj is 0.6 MPa and k is 0.02 MPa m½ at -10°C and 10−6 s−1. This point is illustrated in Figure 2. Fig. 2. Hall-Petch plot showing the relationship between the tensile strength and the grain size of the ice. The d−½ character of this relationship, which is of the classical Hall-Petch form observed frequently in metallic materials, indicates that the tensile strength of ice is controlled by some process involving stress concentration, possibly the propagation of microcracks nucleated by the interactions of dislocations or the propagation of pre-existing defects. Of these, the former is the more probable. The reason is that processes involving dislocation motion, when expressed by the difference of σf – σi, are expected to increase linearly with increasing d−½, whereas processes involving the propagation of pre-existing defects predict a linear relationship between σf and d−½ which extrapolates through the origin. The former behavior is the one observed. It is thus concluded: (i) that the tensile strength of equiaxed and randomly oriented freshwater ice, when deformed slowly at -10°C, decreases with increasing grain size, (ii) that the functional relationship between tensile strength σf and grain size d is σf = σj + kd−½, where σj and k are materials parameters, and (iii) that the tensile strength of polycrystalline ice is controlled by the propagation in a brittle manner of microcracks nucleated by dislocation interactions. Acknowledgement This work was funded by the US Army Research Office, Contract No. DAA G-29-80-C-0064.

scholarly journals Effect of Sample and Grain Size on the Compressive Strength of Ice

1983 ◽  
Vol 4 ◽  
pp. 129-132 ◽  
Author(s):  
Stephen J. Jones ◽  
H. A. M. Chew
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Strain Rate ◽  
Sample Size ◽  
Uniaxial Compressive Strength ◽  
Size Range ◽  
Significant Dependence ◽  
Polycrystalline Ice

The effect of sample and grain size on the uniaxial compressive strength of polycrystalline ice has been investigated at -10°C, at a strain-rate of 5.5 × 10-4s-1The results show (a) that the sample size must be 12 or more times greater than the grain size for ft to have no effect on the strength and (b) that there is no significant dependence of compressive strength on grain size, within the grain-size range of 0.6 to 2.0 mm.

Effect of Solute Elements on Grain Refinement during Friction Stir Processing in High-Purity Aluminum

2016 ◽  
Vol 838-839 ◽  
pp. 116-121 ◽  
Author(s):  
Tokuteru Uesugi ◽  
Hideaki Iwami ◽  
Yorinobu Takigawa ◽  
Kenji Higashi
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Friction Stir Processing ◽  
High Purity ◽  
Critical Role ◽  
Hollomon Parameter ◽  
Friction Stir ◽  
Grain Sizes ◽  
Purity Level ◽  
High Purity Aluminum

Friction stir processing (FSP) is one of the severe plastic deformation (SPD) processes. It has been reported that SPD-processed Al with various purities attained a minimum grain size when Zener-Hollomon parameter is larger than 1016 s-1. The minimum grain size is different by purity level and alloying elements. We investigated the influence of Fe solute atoms on grain refinement of high-purity Al on the condition that Zener-Hollomon parameter was larger than 1016 s-1. FSP was conducted on Al-0.01%Fe, which was fabricated by using 5N Al (99.999% purity). FSP-ed Al-0.01%Fe exhibits the minimum grain size of 1.4 μm, although high-purity aluminums with more than 99.998% exhibits much larger minimum grain sizes of 30-40 μm. Only 101 at.ppm Fe played a critical role in the grain refinement of pure aluminums.

scholarly journals Texture and Grain Growth during the Annealing of Ice

1982 ◽  
Vol 5 (1) ◽  
pp. 19-31 ◽  
Author(s):  
C. J. L. Wilson
Keyword(s):  
Growth Rate ◽  
Grain Size ◽  
Light Microscopy ◽  
Grain Growth ◽  
Annealing Time ◽  
Polarized Light ◽  
Grain Structure ◽  
Grain Sizes ◽  
Polycrystalline Ice ◽  
Textural Change

Changes in microstructure and texture are described in polycrystalline ice compressed at temperatures of –10 and –1℃ and annealed for various times at –1℃ without a load. The microstructures, obtained under these conditions, were studied by means of polarized light microscopy, both mean and maximum grain sizes were determined. In the colder finer grained samples (–10℃) the grain size increase during annealing was not as rapid as the coarser hot worked (–1°) samples. Little textural change was observed in the annealed hot worked samples, however the strong preferred orientation of the colder samples was destroyed with annealing. The change in texture corresponded to a decrease in the grain growth rate and the formation of a stable grain structure. Increasing strain and decreasing the deformation temperature both reduce annealing time and the annealed grain size.

The Grain Refinement of Al-Si Alloys and the Cause of Si Poisoning: Insights Revealed by the Interdependence Model

2014 ◽  
Vol 794-796 ◽  
pp. 161-166 ◽  
Author(s):  
Mark A. Easton ◽  
Arvind Prasad ◽  
David H. St. John
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Master Alloy ◽  
Cost Effective ◽  
Optimum Level ◽  
Grain Sizes ◽  
Relative Contribution ◽  
Master Alloys ◽  
Effective Use ◽  
Special Case

Recent work has extended the Interdependence Model to the prediction of grain size of aluminium alloys when refined by Al-Ti-B master alloys. The relative contribution of Ti solute and TiB2 particles to the as-cast grain size was determined indicating the optimum level of addition required to provide cost effective use of master alloy. This paper quantifies the effect of Al5Ti1B master alloy additions on the grain size of Al-Si alloys. The Al-Si system is a special case where additions of Si above a few percent poison grain refinement resulting in larger grain sizes. Consideration of the complicating effect of Si poisoning on the prediction of the grain size of these alloys and possible approaches to dealing with these complications are presented.

scholarly journals The Tensile Strength of Polycrystalline Ice (Abstract only)

1983 ◽  
Vol 4 ◽  
pp. 305-305
Author(s):  
E. M. Schulson ◽  
J. H. Currier
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Functional Relationship ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Structure Property ◽  
Property A ◽  
Freshwater Ice ◽  
Polycrystalline Ice ◽  
Image Position

Structure/property relationships, while well-researched in metallic and in some ceramic materials, have been essentially ignored 1n studies on the mechanical properties of ice. To rectify this situation, experiments have been designed and have been underway for the past two years to investigate one mechanical property, i.e. tensile strength, and the effect of one structural feature, i.e. grain size, on this property. A clear relationship has been established, and is reported here. Other work is in progress and will also be reported in due course.Equiaxed and randomly oriented aggregates of freshwater ice, of grain size (as seen in two-dimensional sections) varying from 1.0 to 7.3 mm, were prepared in the form of large cylinders (91 mm diameter × 231 mm length). The aggregates were deformed to fracture under uniaxial tension, using a specially designed ball-joint and yoke assembly to ensure axial loading. Data were obtained at -10 ±0.2°C (i.e. at 96% of the melting point) at a strain-rate of 10−6 s−1.Figure 1 shows that the tensile strength decreases with increasing grain size, from 1.25 MPa for d = 1 mm to 0.80 MPa for d = 7 mm. Moreover, this figure illustrates that the data are highly reproducible; i.e. that strength is reproducible to within ±5% for a given grain size over the complete range. Fig. 1.Graph showing the decrease in the tensile strength of ice with increasing grain size.Concerning the functional relationship between tensile strength of and grain size, analysis shows that the following equation is well obeyed:Where σj is 0.6 MPa and k is 0.02 MPa m½ at -10°C and 10−6 s−1. This point is illustrated in Figure 2. Fig. 2.Hall-Petch plot showing the relationship between the tensile strength and the grain size of the ice.The d−½ character of this relationship, which is of the classical Hall-Petch form observed frequently in metallic materials, indicates that the tensile strength of ice is controlled by some process involving stress concentration, possibly the propagation of microcracks nucleated by the interactions of dislocations or the propagation of pre-existing defects. Of these, the former is the more probable. The reason is that processes involving dislocation motion, when expressed by the difference of σf – σi, are expected to increase linearly with increasing d−½, whereas processes involving the propagation of pre-existing defects predict a linear relationship between σf and d−½ which extrapolates through the origin. The former behavior is the one observed.It is thus concluded: (i) that the tensile strength of equiaxed and randomly oriented freshwater ice, when deformed slowly at -10°C, decreases with increasing grain size, (ii) that the functional relationship between tensile strength σf and grain size d is σf = σj + kd−½, where σj and k are materials parameters, and (iii) that the tensile strength of polycrystalline ice is controlled by the propagation in a brittle manner of microcracks nucleated by dislocation interactions.AcknowledgementThis work was funded by the US Army Research Office, Contract No. DAA G-29-80-C-0064.

scholarly journals Effect of Sample and Grain Size on the Compressive Strength of Ice

1983 ◽  
Vol 4 ◽  
pp. 129-132 ◽  
Author(s):  
Stephen J. Jones ◽  
H. A. M. Chew
Keyword(s):  
Grain Size ◽  
Compressive Strength ◽  
Strain Rate ◽  
Sample Size ◽  
Uniaxial Compressive Strength ◽  
Size Range ◽  
Significant Dependence ◽  
Polycrystalline Ice

The effect of sample and grain size on the uniaxial compressive strength of polycrystalline ice has been investigated at -10°C, at a strain-rate of 5.5 × 10-4 s-1 The results show (a) that the sample size must be 12 or more times greater than the grain size for ft to have no effect on the strength and (b) that there is no significant dependence of compressive strength on grain size, within the grain-size range of 0.6 to 2.0 mm.

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