Which is the stiffest025 Why0 5 Which is the hardest025 Why0

Which is the stiffest?(0.25) Why?(0, 5) Which is the hardest?(0.25) Why?(0, 5) Consider metal single crystal oriented such that the slip direction and the normal to the slip plane are at angles of 30 degree and 70 degree, respectively, with the tensile axis. If the crystal to yield? If not, what stress will be necessary?

Solution

Solution

This problem calls for us to determine whether or not a metal single crystal having a specific orientation and of given critical resolved shear stress will yield.

We are given that = 30°, = 70°, and that the values of the critical resolved shear stress and applied tensile stress are 6 MPa and =15 MPa respectively.

                                       R = cos cos = 15* cos 30 *cos 70 = 4.4429 Mpa

  Since the resolved shear stress (4.4429 MPa) is less than the critical resolved shear stress

( 6MPa), the single crystal will not yield.

However, the stress at which yielding occurs is

                                                  y =    /(cos cos ) = 6/ cos 30 *cos 70 =20.256 Mpa

necessary stress will be y =20.256 Mpa