Nickel has a Hall-Petch coefficient of 0.13 MPa(m3/2) and a friction stress of 60 MPa. Its shear modulus is 76 GPa and its Burgers vector is 0.25 nm. Assuming that the grain size (diameter) determines a minimum bowing stress (asgiven by the FUNDAMENTAL strengthening formula), plot both the flow stress determined from the Hall-Petch equation, and the bowing stress (on the same graph) as a function of grain size, d. Use logarithmic axes in order to cover the range 1nm sds 1mm. Assume an average Taylor factor appropriate for randomly oriented polycrystals, =3.1. Below what grain size does the Orowan bowing stress become dominant? Nickel has a Hall-Petch coefficient of 0.13 MPa(m3/2) and a friction stress of 60 MPa. Its shear modulus is 76 GPa and its Burgers vector is 0.25 nm. Assuming that the grain size (diameter) determines a minimum bowing stress (asgiven by the FUNDAMENTAL strengthening formula), plot both the flow stress determined from the Hall-Petch equation, and the bowing stress (on the same graph) as a function of grain size, d. Use logarithmic axes in order to cover the range 1nm sds 1mm. Assume an average Taylor factor appropriate for randomly oriented polycrystals, =3.1. Below what grain size does the Orowan bowing stress become dominant