Materials Science and Engineering: An Introduction

$σ = +58.2 MPa$, tensile
Given: As in Part (a), but now $T_{f} = -15 °C$ Required: type and magnitude of stress Solution: $σ = Eα_{l}(T_{0} - T_{f}) = (97 \times 10^{3} MPa)(20.0 \times 10^{-6} (°C)^{-1})(15 °C - (-15°C)) \\ = +58.2 MPa$ Since the computed value is positive, the stress is tensile.