Question

20 points. The frictional shear stress to move a dislocation through a perfect crystal is given by Ti = G exp((-2nd / b(1-v)) where d is the atomic spacing on close packed plane and b is the magnitude of the Burgers vector. Calculate ty for an fcc Cu crystal, if the dislocation is a Shockley partial. The shear modulus Cu is 42 GPa, its Poisson's ratio is 0.3, and its lattice parameter is 3.618.

Answer 1

5 of shockley partial ao [257] n Qo ibts 36 151 Qo V4+147 36 ao given a o= 3.61 nom A b = 47 A 3.61 ro close packed plane in fcc is (111) plane 3.61 3.6) dz B 2 Үх усt! Yhtk Arth ei da 2.08 Given G= uz G= 42 GPa; "=0.3 -) G exp (-27d 1 -27X2-08 T: 2 b(1-0) = 42 * expl 1:47(1-0.3) 2 42x109x3.049810 -6 Te 02128 Apa To = 0.13 1 MPa CS Scanned with CamScanner