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Nama : Dewi Lestari Natalia

Jurusan : Teknik Metalurgi & Material

NPM : 1006704530

Question 1

A. In your own words, describe what is a metal?

B. What makes metals are commonly ductile?C. Are metallic materials usually crystalline or amorphous? Offer your explanation.

D. Give three examples of engineering application of metals.

E. Compare the possible fracture surface of metals, ceramics and polymers on the samescale.

F. Why do ceramic materials have lower ductility than metallic materials?

G. Dissemble a torch. Investigate: (i) how many parts do you find in a torch, (ii)investigate on what type of materials each part is made of.

Answer 1

A. Metal is materials which compose of one or more metallic elements (such as iron,

aluminum, copper, titanium, etc) and often also nonmetallic elements (for examples,

carbon, nitrogen, and oxygen) in relatively small amounts. Metal also has high strengthand readily deformable, yet ductile, and good conductors of electricity and heat.

B. The way in which atoms are arranged and their metallic bonds make metals arecommonly ductile. High degrees of ductility occur due to metallic bonds, which are

found predominantly in metals and leads to the common perception that metals are

ductile in general.

C. Metallic materials usually crystalline because atoms in metallic material and their

alloys are arranged in a very orderly manner and in comparison to the ceramics and

polymers relatively dense.

D. Railway technology, locomotive engines, and boogies.

E. The possible fracture surface of metals, ceramics, and polymers on the same scale :

Metals are resistant to fracture, ceramics are highly susceptible to fracture, and polymers

are not too resistant and also not too susceptible to fracture.

F. Ceramics are extremely brittle. Its because ceramics dont have metallic bonds like

metals but they have ionic bonds and covalent bonds.

G. There are some parts in a torch, usually a rod-shaped piece ofwood with a rag soaked

inpitch and/or some otherflammable material wrapped around one end. Each part is

made of insulator and conductor material types.

http://en.wikipedia.org/wiki/Metallic_bondhttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/wood&rurl=translate.google.co.id&usg=ALkJrhj4x1N4NDfa67yrJqTQ5VCb99nobAhttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/rag-7&rurl=translate.google.co.id&usg=ALkJrhj8E0DwAjo3TQKKSZcY3HiBTnnV8Ahttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/pitch&rurl=translate.google.co.id&usg=ALkJrhhOpXgYPcwEGU9T4y8rqGZ2YDuvjghttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/inflammability&rurl=translate.google.co.id&usg=ALkJrhhoIHNGLREJ0kg7yhW7cnHMze6TLghttp://en.wikipedia.org/wiki/Metallic_bondhttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/wood&rurl=translate.google.co.id&usg=ALkJrhj4x1N4NDfa67yrJqTQ5VCb99nobAhttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/rag-7&rurl=translate.google.co.id&usg=ALkJrhj8E0DwAjo3TQKKSZcY3HiBTnnV8Ahttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/pitch&rurl=translate.google.co.id&usg=ALkJrhhOpXgYPcwEGU9T4y8rqGZ2YDuvjghttp://translate.googleusercontent.com/translate_c?hl=id&langpair=en%7Cid&u=http://www.answers.com/topic/inflammability&rurl=translate.google.co.id&usg=ALkJrhhoIHNGLREJ0kg7yhW7cnHMze6TLg

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Question 2

A. Compare the general characteristics of metals, polymer and ceramics and give 5

examples of theapplication of the three materials.

B. What is composite material? Give three examples of structures made of composite

materials.C. Describe and give examples of crystalline and amorphous materials.

D. Describe ionic bonding and give three examples of materials having this kind of

bonding.E. Describe metallic bonding and the properties of materials possessing metallic bonding.

Answer II

A.

Materials Characteristics Examples

Metals metallic bonding

much of the periodictable

high strength

readily deformable,ductile

good conductors of

electricity and heat

Jewelry

BoogiesSilverware

Coins

Bolt

Polymer covalent + van der

Waals bonds

organic - carbon,

hydrogen

extremely flexible

light weight

corrosion resistance

low cost

Plastic tableware

Billiard ballPipe

Plastic bottle

Gallon

Ceramics distinctive by ionic

or covalent bonding

high strength and

hardness

excellent

temperature stability

thermal andelectrical insulator

brittle

Mirror

Glass

Floor tileRoof tile

Glass vase

B. Composite material is composed of two (or more) individual materials, which comefrom the metals, polymers, or ceramics. The design goal of composite is to achieve a

combination of properties that is not displayed by any single material, and also to

incorporate the best characteristics of each of component materials. The structures made

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of composite materials are fiberglass, aircraft and aerospace application, and high-tech

sporting equipment.

C.

Crystalline material : atoms are arranged in a repeating or periodic array over

large distances. Examples: quartz, metals. Amorphous material : atoms are randomly arranged. Example: glass.

D. Ionic bonding always found in compounds that are composed of both metallic and

nonmetallic elements, required electron transfer, and large difference in electronegativityrequired. Examples: NaCl, MgO, dan CaF2 .

E. Metallic bonding is found in metals and their alloys. A relatively simple model has

been proposed that very nearly approximates the bonding scheme. Metallic bonding isfound for Group IA and IIA elements in the periodic table, and, in fact, for all elemental

metals. The properties of materials possessing metallic bonding usually high strength,

readily deformable, ductile and good conductors of electricity and heat