Chapter 7: Problem 5
(a) Define a slip system. (b) Do all metals have the same slip system? Why or why not?
Chapter 7: Problem 5
(a) Define a slip system. (b) Do all metals have the same slip system? Why or why not?
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Get started for free(a) What is the approximate ductility (\%EL) of a brass that has a yield strength of 345 MPa \((50,000 \mathrm{psi}) ?\) (b) What is the approximate Brinell hardness of a 1040 steel having a yield strength of 620 MPa \((90,000 \mathrm{psi}) ?\)
Experimentally, it has been observed for single crystals of a number of metals that the critical resolved shear stress \(\tau_{\text {crss }}\) is a function of the dislocation density \(\rho_{D}\) as $$ \tau_{\mathrm{crss}}=\tau_{0}+A \sqrt{\rho_{D}} $$ where \(\tau_{0}\) and \(A\) are constants. For copper, the critical resolved shear stress is \(0.69 \mathrm{MPa}\) (100 psi) at a dislocation density of \(10^{4} \mathrm{~mm}^{-2}\). If it is known that the value of \(\tau_{0}\) for copper is \(0.069 \mathrm{MPa}\) (10 psi), compute \(\tau_{\text {crss }}\) at a dislocation density of \(10^{6} \mathrm{~mm}^{-2}\).
The following yield strength, grain diameter, and heat treatment time (for grain growth) data were gathered for an iron specimen that was heat treated at \(800^{\circ} \mathrm{C}\). Using these data, compute the yield strength of a specimen that was heated at \(800^{\circ} \mathrm{C}\) for \(3 \mathrm{~h}\). Assume a value of 2 for \(n\), the grain diameter exponent. $$ \begin{array}{lcc} \hline \begin{array}{l} \text { Grain } \\ \text { diameter } \\ (\mathbf{m m}) \end{array} & \begin{array}{c} \text { Yield } \\ \text { Strength } \\ \text { (MPa) } \end{array} & \begin{array}{c} \text { Heat } \\ \text { Treating } \\ \text { Time (h) } \end{array} \\ \hline 0.028 & 300 & 10 \\ \hline 0.010 & 385 & 1 \\ \hline \end{array} $$
A single crystal of zinc is oriented for a tensile test such that its slip plane normal makes an angle of \(65^{\circ}\) with the tensile axis. Three possible slip directions make angles of \(30^{\circ}, 48^{\circ}\), and \(78^{\circ}\) with the same tensile axis. (a) Which of these three slip directions is most favored? (b) If plastic deformation begins at a tensile stress of \(2.5 \mathrm{MPa}\) (355 psi), determine the critical resolved shear stress for zinc.
A cylindrical rod of steel \(\left(E=207 \mathrm{GPa}, 30 \times 10^{\circ}\right.\) psi) having a yield strength of \(310 \mathrm{MPa}(45,000\) psi) is to be subjected to a load of \(11,100 \mathrm{~N}\) (2500 \(\left.\mathrm{Ib}_{i}\right)\). If the length of the rod is \(500 \mathrm{~mm}(20.0 \mathrm{in}\).), what must be the diameter to allow an elongation of \(0.38 \mathrm{~mm}(0.015\) in.)?
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