Engineering Materials MCQ Questions & Answers | Mechanical Engineering

Invar is an alloy of iron and nickel with a negligible coefficient of expansion,.
and it is used in the making of clocks and scientific instruments like surveying tapes

a prism of brittle material when subjected to stress, it breaks without significant plastic deformation.
Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a snapping sound.

Lower bainite is a microstructure in steel that forms at temperatures slightly above the martensite start temperature but lower than the range for upper bainite formation.

It is considered a form of tempered martensite because it consists of fine ferrite plates with dispersed carbide particles, which provide a good balance of strength and toughness.

When martensite is tempered, its extreme hardness is reduced to improve toughness, but lower bainite retains a relatively high hardness compared to other tempered structures.

On the Rockwell C (RC) scale, lower bainite typically measures around RC 57, making it harder than RC 48 but softer than untempered martensite at RC 65 or above.

This hardness level is ideal for applications needing both high strength and improved ductility.

Cast iron is a material that behaves differently under compression (being squeezed) and tension (being pulled).

* Tensile Strength: This is how much pulling force the material can withstand before breaking.
* Compressive Strength: This is how much squeezing force the material can withstand before crushing.

Cast iron is stronger when it's being squeezed (compressed) than when it's being pulled (tensioned).

Think of it this way: Cast iron is brittle and prone to cracking when pulled, but it can handle a lot of crushing force.

So, the compressive strength of cast iron is much greater than its tensile strength.

Chromium when added to steel to Increases the tensile strength.

shock resisting steel that offers good ductility and toughness at high hardness levels. It exhibits high strength and adequate abrasion resistance for those applications involving shock or impact loading.

White metal contains Alloy of tin, lead and cadmium

Aluminium bronze is used for imitation jewellery

Large forgings, crank shafts, axles made from cast iron or forged steel. Steel is usually used in high loading situations,
and this steel contains carbon up to 0.45 to 0.55%.

Cemented carbide tools are not found to be suitable for cutting Steel