Question

Plastic & Paper come in thin sheets, but they are not malleable. Why?

Answer 1

Answer:

please maked me in brainlisets.

Explanation:

By definition, ductile materials are those that undergo significant plastic deformation prior to fracture. The usual mechanism of plastic deformation is by slip, one part of the crystal slides over another part separated by a slip plane. Slip requires shear stress on the slip plane in the slip direction (called critical resolved shear stress). Thus the failure is by shear.

Of course, the externally applied stress can be tensile or complex. But it should provide a shear stress on the slip plane in the slip direction. Furthermore, micromechanically, the slip is aided by the presence of dislocations.

Brittle materials do not undergo significant plastic deformation. They thus fail by breaking of the bonds between atoms, which usually requires a tensile stress along the bond. Micromechanically, the breaking of the bonds is aided by presence of cracks which cause stress concentration.

I hope you answer.