The grain size

The solid phase of soil contains particles of different sizes, and it has different textures. The granulometric analysis of the soil presents data about the relative (percentage) abundance of particles of a certain size and it serves as a basis for soil categorization. 

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Small amounts of yttrium (0.1 to 0.2%) can be used to reduce the grain size in chromium, molybdenum, zirconium, and titanium, and to increase strength of aluminum and magnesium alloys. 

Grain size varies widely, from 10 to 5000 nm. The grain size of fine-grained or banded deposits is usually 10—100 nm. Some metals, notably copper, nickel, cobalt and gold, can be deposited in all four types of grain stmcture, depending on the solution composition and plating conditions. 

Another commercial development of the 1970s is the appHcation of superplasticity which is exhibited by a number of zinc alloys (135—138). Under the right conditions, the material becomes exceptionally soft and ductile and, under low stresses, extensions exceeding 1000% can be obtained without fracture. The grain size must be extremely small (about 1 micrometer) and stable. This grain size is less than one tenth that of common metals in the wrought condition. 

It may be easier to fit the parameters by forcing them to follow specified functional forms. In earhest attempts it was assumed that the forms should be normahzable (have the same shape whatever the size being broken). With complex ores containing minerals of different friability, the grinding functions S and B exhibit complex behavior near the grain size (Choi et al., Paiiiculate and Multiphase Processes Conference Proceedings, 1, 903-916.) B is not normalizable with respecl to feed size and S does not follow a simple power law. 

Ceramics, on the other hand, often deform predominantly by diffusional flow (because their grains are small, and the high lattice resistance already suppresses power-law creep). Special heat treatments to increase the grain size can make them more creep-resistant. 

Material properties for ice are listed in Table 28.3. The fracture toughness is low (0.12 MPa m ). The tensile strength of ice is simply the stress required to propagate a crack of dimensions equal to the grain size d, with... 

Grain size in textured films. For films having a preferred growth direction—e.g., (111)—LEED can be used to determine the preferred direction and the grain size parallel to the surfrce. The preferred direction is obtained from the symmetry of the diffraction patterns, while the grain size is obtained from the shape in angle of diffracted beams. 

Figure 5 Atomic force microscope images of an aluminum film deposited on ambient (a) and heated (b) Si substrates. The scales are 15 pm x 15 pm (a) and 20 pm x 20 pm (b). The grain size can be clearly observed (Courtesy of M. Lawrence A. Dass, Intel Corporation).

Figure 4.1. Wrought low-carbon mild steel, annealed and impressed by a Brinell ball (12 mm diameter), then annealed. "tO min at 750°C and sectioned. The grain size is largest just inside the zone beyond which the critical strain for recrystallisation has not quite been attained (after Hanemann and Schrader 1927. courtesy M. Hillert).

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