31 Aug What is the difference between crystalline and noncrystalline structures in materials?

Q 2.4 What is the difference between crystalline and noncrystalline structures in materials?

Describe each structure; (2) Provide one material property to show it is impacted by the difference between two structures.

Q 2.8 Define the difference between elastic and plastic deformation in terms of the effect on the crystal lattice structure.

Describe each deformation; (2) Indicate under what force the crystal structure will have plastic deformation.

Q 2.9 Identify some materials that have a crystalline structure.

Provide 2 material examples for BCC, FCC, and HCP, respectively.

Q 3.2 State Hooke’s law

Describe Hooke's Law; (2) provide the equation to define Hook's Law and define each parameter/variable included in the equation.

Q 3.4 Define yield strength of a material.

Define yield strength; (2) Indicate where to find the yield strength on a stress-strain plot.

P 3.2 (SI Units) In a tensile test, the starting gage length = 100.0 mm and the cross-sectional area = 150 mm2. During testing, the following force and gage length data are collected: (1) 17,790 N at 100.2 mm, (2) 23,040 N at 103.5 mm, (3) 27,370 N at 110.5 mm, (4) 28,910 N at 122.0 mm, (5) 27,480 N at 130.0 mm, and (6) 20,460 N at 135.1 mm. The final data point (6) occurred immediately prior to failure. Yielding occurred at a load of 19,390 N (0.2% offset value), and the maximum load (4) was 28,960 N. (a) Plot the engineering stress strain curve. Determine (b) yield strength, (c) modulus of elasticity, (d) tensile strength, and (e) percent elongation.

Refer to Example 3.1 of your e-textbook: (1) Create a table to show the pair relationship between stress and strain and then make a plot similar to Figure 3.4 with numerical values from the table you create; (2) show your calculation and answer to each part asked in this question.

P 3.20 (SI/USCS Units) In a Brinell hardness test, a 1500-kg load is pressed into a specimen using a 10-mm-diameter hardened steel ball. The resulting indentation has a diameter = 3.2 mm. (a) Determine the Brinell hardness number for the metal. (b) If the specimen is steel, estimate the tensile strength of the steel.

The solution to this question is provided in the e-textbook, so you can understand, copy, and pate it to earn 50% of the full credit. To earn the remaining 50% credit, you need to attach an Excel file to show how you set up your equations to calculate your answers using the functions built into the Excel sheet.

(a) HB = 2(1500)/(10π(10 − (102 − 3.22).5) = 3000/(10π × 0.5258) = 182 BHN

(b) The estimating formula is: TS = 500(HB).

For a tested hardness of HB = 182, TS = 500(182) = 91,000 lb/in^2

4.8 What is thermal conductivity as a material property?

(1) Define thermal conductivity (not thermal conduction); (2) describe how it is affected by other factors.

Q 4.14 Define electrical conductivity as a material property.

1) Define electrical conductivity (not electrical conduction); (2) describe how it is affected by other factors.

P 4.3 (SI units) A bridge to be fabricated of steel girders is designed to be 500 m long and 12 m wide at ambient temperature (assumed 20°C). Expansion joints will be provided to compensate for the change in length in the girders as the temperature varies. Each expansion joint can compensate for a maximum of 20 mm of change in length. From historical records it is estimated that the minimum and maximum temperatures in the region will be −35°C and 40°C, respectively. Determine (a) the minimum number of expansion joints required and (b) the length that each bridge section should be fabricated. The coefficient of thermal expansion α=12(10−6)/C for steel.

Please refer to Equation (4.1) and Table 4.1 of your e-textbook: Show your calculation and answer to solve each part of this problem; note that there is no partial joint, and the number of joints should be an integer.

P 4.4 (SI units) Aluminum has a density of 2.70 g/cm3 at room temperature (20 °C). Determine its density at 500 °C.

Please refer to Equation (4.1) and Table 4.1 of your e-textbook: Show your calculation and solve this problem; note that density = mass/volume and change in volume = (change in length) x (change in width) x (change in height) and you can assume a cube in this problem.