Why does dislocation have influence on mechanical properties of metallic materials but not on glass? You are the production engineer in a steel manufacturing company and a client who purchased one of the company’s product is complaining of brittle behaviour of product purchased from your company. You realized there was no dislocation in those products. How will you explain to him that it was due to lack of dislocation that accounted for such brittle behaviour? Sketch the following planes and directions within a cubic unit cell: [ 3 ¯ 2 ¯ 1] [ 2 1 ¯ 3] ( 2 ¯ 1 2) (0 4 ¯ 1)