Engineering Materials
Thermoplastic materials are those materials which

Are used as a friction lining for clutches and brakes
Are formed into shape under heat and pressure and results in a permanently hard product
Do not become hard with the application of heat and pressure and no chemical change occurs
Are flexible and can withstand considerable wear under suitable conditions

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Engineering Materials
Ductile cast iron

Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable
Is produced by annealing process. It is soft, tough and easily machined metal

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Engineering Materials
Which of the following statement is true about brittle fracture?

Brittle fracture is always preceded by noise
High temperature and low strain rates favour brittle fracture
Many metals with hexagonal close packed (H.C.P) crystal structure commonly show brittle fracture
Cup and cone formation is characteristic for brittle materials

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