Material Science - short answer questions from AMIE exams

Cup and cone type of fracture is characteristic of which type of material?
Cup and cone fracture is characteristic of moderately ductile material. The formation of the cup and cone fracture surface occurs in stages. Initially, as a result of the tensile load, the material stretches and experiences plastic deformation. Beyond some point, the material will begin to neck.

Which two parameters constitute a slip system?
Slip plane and slip direction constitute slip system.

What is the essential difference between a brittle fracture and a ductile fracture?
Little or no plastic deformation in brittle fracture and large plastic deformation in ductile fracture.

Is it possible to determine stress in a body without measuring corresponding strain?
Yes by measuring force and area.

What is the essential difference between thermoplastic and thermoset polymers?
Thermoplastic polymer softens on heating while thermosetting sets or hardens.

What are the three stages of creep deformation?
Decreasing rate of strain, constant rate of strain and increasing rate of strain are three stages in creep deformation. 

Polyvinyl chloride can exist in many stereoisomeric forms. Which form does not crystallize easily.
A tactic stereotactic polyvinyl polymer chloride does not crystallize easily.

For which type of fracture, the direction of crack propagation is very nearly perpendicular to the direction of applied tensile stress?
Brittle type of fracture

Name the metal known to have the highest electrical conductivity.
Silver has the highest electrical conductivity at normal temperatures.

Which type of material shows the necking phenomenon just before fracture and what is the common name for such a fracture?
The ductile material shows the necking phenomenon. The common name for such fracture is cup and cone fracture. 


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