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Unformatted text preview: Specify a practical precipitation heat treatment in terms of temperature and time that would give these mechanical characteristics. Justify your answer. Hint: See Figures 11.27a Chapter 12 Q4: The modulus of elasticity for beryllium oxide (BeO) having 5 vol% porosity is 310 GPa (45 × 10 6 (a) Compute the modulus of elasticity for the nonporous material. psi). (b) Compute the modulus of elasticity for 10 vol% porosity. Chapter 13 Q5: The viscosity η of a glass varies with temperature according to the relationship η= A exp Q vis RT where Q vis is the energy of activation for viscous flow, A is a temperature-independent constant, and R and T are, respectively, the gas constant and the absolute temperature. A plot of ln η versus l/ T should be nearly linear, and with a slope of Q vis (a) make such a plot for the borosilicate glass, and /R . Using the data in Figure 13.7, (b) determine the activation energy between temperatures of 500 and 900°C....
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- Spring '08