74) Epoxy is a(n) ? a) elastomer b) thermoset c) thermoplastic d) composite . 75

ID: 930152 • Letter: 7

Question

74) Epoxy is a(n) ?

a) elastomer

b) thermoset

c) thermoplastic

d) composite

75) In tempering of steel, temperature treatments around 400 °C are used to?

a) reduce brittleness and increase ductility (toughen) by transforming martensite morphology

b) increase strength and hardness by locking in martensite structure

c) increase strength and hardness by causing lower density glass layer to form on surface

d) reduce brittleness and increase ductility (toughen) by causing martensite morphology to form

76) Surface carburizing of steel involves

a) burning excess carbon out of the iron carbon alloy to form steel.

b) introducing extra carbon into surface of austenite to harden and toughen surface with quenching and formation of martensite.

c) forming martensite on the surface through rapid cooling to harden and toughen surface with quenching.

d) introducing extra carbon into surface of cementite to harden and toughen surface with quenching.

Please answer all of them without guessing!!! Thanks

1. thermoset

2.c) increase strength and hardness by causing lower density glass layer to form on surface

3.b) introducing extra carbon into surface of austenite to harden and toughen surface with quenching and formation of martensite.

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