Week 4: Materials

During Week 4 we learn about the different kinds of materials that make up our world.

These materials are all around us and are used to dictate the history of mankind. Going from the stone age where stone tools where used, this goes on to the Bronze age where we managed to make an alloy of copper and tin to make bronze which is stronger each of the individual components. Afterwards it progresses to the iron age, where iron, cast iron and steel is mainly used. Followed by the age of the light alloys where aluminium and titanium are used, afterwards it progresses to the age of plastics. Today we are in the age of nanomaterials, biomaterials and green materials. Classification of materials

Materials can be classified into various categories that each has their own benefits and uses.

1. Natural materials

This encompasses materials like wood, leather bone, cotton and silk. They are renewable and can be grown.

2.Metals & Alloys

These are materials like Iron and Copper which are pure metals, Bronze and Steel which are alloys. These alloys can be further classified into ferrous and non-ferrous alloys which means if they do or do not contain iron in their alloying respectively. These materials tend to have relatively high stiffness, strength, thermal conductivity and good conductor of electricity.

3.Ceramics

Ceramics are inorganic compounds and are generally clay based. They are brittle but hard. They are poor conductors of electricity and heat. They are generally used in porcelain like porcelain bowls and cups in our house.

4.Polymers

Polymers can be further classified into: Thermoplastics, Thermosets and Elastomers.

Thermoplastics: They are relatively soft and flexible among the polymers. They will soften when enough heat is added and will reharden once the heat is removed. A common thermoplastics is Nylon.

Thermosets: They do not soften when heated unlike thermoplastics but rather will char like charcoal and breakdown. They are relatively rigid and hard. A common thermosets is Epoxy.

Elastomers: They are elastic and soft, when heated they will either harden or soften which cannot be reversed and hence may have undesirable effects. A common elastomers is Rubber.

5.Composites

They are made of of 2 or more materials combined together to achieve the best of both materials combined. Some composites you may know includes: fibreglass which is a composite of glass and a polymer. Reinforced concrete which is normal concrete with steel rebar added to improve strength.

Materials Selection

How would you know which material to use? Well, the right material needs to take into consideration the purpose of the material, the cost, availability, how environmental is it and lastly how to even manufacturer the item you want. Hence a great material is able to balance all these factors to make a great product.

Blogged by:

Pedro Tay

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