4.2a Metal and Metallic Alloys

What is a super alloy?

A group of metal alloys that all feature high temp. strength and resistance to thermal shock + high temp. oxidation

What applications are there for super alloys?

In high temperature service, like jet/rocket engines and chemical plants.

What is ore?

a naturally occurring solid material from which a metal or valuable mineral can be profitably extracted.

What does ore contain?

metal/valuable minerals

How do we get ore?

Mining from the earth

What is smelting?

extract (metal) from its ore by a process involving heating and melting.

In Steel and Aluminum, what are the chemical reactions that happen in the smelting process?

Iron ore, coke and limestone react to the hot air blast in the steel lined brick smelting process to create slag

What is an alloy?

A mixture of two or more metals, or a metal and a non-metal

What can we do with metals me recycle?

Smelt and reuse them

Whey should we recycle metals?

It's cheaper in terms of resources used

How many time can we recycle the same metal?

As much as wanted, they have an unlimited lifespan

What is a metal?

Elements that are good conductors of electric current and heat. (+shiny)

What are crystals?

solids whose particles are arranged in a lattice structure

What is a crystal lattice?

a three-dimensional geometric arrangement of particles

What is alloying?

By melting and mixing a metal with other metals or some non-metals, its properties can changed. This process is called alloying.

Why do we make alloys?

to strengthen or weaken the properties of the metals we are using

what is annealing?

When metals are heated until they are red hot and then cooled slowly

What is work hardening?

the increase in strength that occurs in metals when they are strained.

What is tempering?

a heat treatment technique applied to ferrous alloys to achieve greater toughness by decreasing the hardness of the alloy. The reduction in hardness is usually accompanied by an increase in ductility, thereby decreasing the brittleness of the metal.

What difference is there between the grain size for steel and a super alloy?

Steels grains can be big or small, which just means the steel with either be strong/flexible, or tougher. For superalloys, grains are tiny and spread evenly to handle high heat/stress.

What are the three groups of super alloys?

Nickel-based, Cobalt-based, and Iron-based

What are Nickel-based alloys used for?

Super strong + can handle high temperatures

What are Cobalt-based superalloys used for?

Resistant to wear/high temperature situations

What are Iron-based superalloys used for?

Rust-resistant and can endure high temperatures

What is creep?

When metals slowly move/deform permanently as a result of long-term exposure to stress

What is oxidation resistance?

Ability of a metal to resist the direct/indirect of e oxygen (oxidation)