2 -- annotated -- Crystals, dislocations and slip

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Which of the following are true regarding crystalline and non-crystalline materials at the atomic scale? Select one or more: a. Crystalline materials show no long-range order b. There are an infinite number of crystal systems and lattices possible C. Density of packing is higher for crystalline materials d. Bond energy is lower for noncrystalline materials Materials which are not crystalline are referred to as amorphous Bond length is shorter for crystalline versus noncrystalline materials e.

Grain size does not have a major influence on mechanical properties. True False   Identify the crystal in the picture.

Qu. 15 What are the indices for the Plane 1 drawn in the following sketch? Qu. 16 What are the Miller indices for the Plane shown in the following cubic unit cell? this is material engineering please show all work

A number of elements along with their crystal structures and atomic radii are listed in the following table. Which pairs might be expected to have complete solid solubility in each other? Crystal Atomic Crystal Structure Atomic Structure radius (nm) radius (nm) Silver Palladium FCC 0.144 Lead FCC 0.175 FCC 0.137 0.137 Tungsten Rhodium ВСС Copper Gold FCC 0.128 FCC 0.134 Platinum Tantalum FCC 0.144 FCC 0.138 Nickel FCC 0.125 ВСС 0.143 Aluminum Sodium FCC 0.143 Potassium ВСС 0.231 ВСС 0.185 Molybdenum ВСС 0.136

Consider a defect in a crystalline lattice as shown below. Which of the following statements is true? B Select one: O a. The region around B experiences a higher strain on the upper side compared to the lower side O b. The region around B experiences mainly shear strain O c. The region around B experiences mainly compressive strain O d. The region around B is unaffected by the impurity

Consider a dislocation condition as shown below. A) what is the strain state in the upper region and B) how would addition of small impurity atoms in the region indicated by "*"s change it? oooooo OOOOO DO Select one: a. Compressive, would reduce compressive strain O b. Tensile, would decrease tensile strain O C. Compressive, would increase compressive strain Od. Tensile, would increase tensile strain Oe. Shear, would increase compressive strain

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Which of the following statements are true of dislocations: Select one or more: a. Dislocations are spatially fixed defects b. Dislocations arise due to insertion of a foreign atom into a lattice site of a “host” metal c. Dislocations can be viewed without the aid of a microscope d. Dislocations enable plasticity in metals e. Dislocations can arise due to shear deformation of the lattice

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Incorrect Question 6 What are the Miller indices for plane 2 in the image shown? 0.2 nm- (020) (324) Plane 2 Note that the plane intercept x axis at +0.2 nm and y axis at -0.2 nm. Ⓒ (221) -0.4 nm- None of these (221) Plane 1 0.4 nm

Consider a dislocation condition as shown below. A) what is the strain state in the upper region and B) how would addition of small impurity atoms in the region indicated by "*"s change it? OOOOOO ooooooo OO OO O O O O O O O O O O O O Select one: a. Tensile, would increase tensile strain b. Shear, would increase compressive strain c. Tensile, would decrease tensile strain O d. Compressive, would reduce compressive strain e. Compressive, would increase compressive strain

Which of the following statements are true? Select one or more: a. Dislocations and defects make thermal transfer easy due to plastic deformation b. Starting at room temperature, the heat conductivity of ceramics goes generally up with increasing temperature c. Starting at room temperature, the heat conductivity of ceramics goes generally down with increasing temperature  d. Dislocations and defects make thermal transfer difficult due to phonon scattering e. Heat transfer in solids occurs mainly by waves of atoms vibrating f. Heat transfer in solids occurs mainly by phonons

question j620 Find the Miller indices of each crystallographic plane