BTEC assignment-engineering materials help?

[Martin T]

Hello everybody
I'm just trying to do my assignment for my engineering NVQ on
'Properties and Applications of Engineering Materials'
And I've done the applications and the properties of the materials
however I cant seam to find the structure of some of the materials
(for example Face-Centred Cubic Structure)
I was wondering if anybody here knew any of them:-

-High Carbon Steel
-Copper
-Brass
-PVC
-Polypropylene
-crystalline ceramics
-GRP composite
-Piezo electric materials

It would be much appreciated if anybody could help as i know there is a few engineers on this now and again

thanks

[aeroluke]

Martin T said:

Hello everybody
I'm just trying to do my assignment for my engineering NVQ on
'Properties and Applications of Engineering Materials'
And I've done the applications and the properties of the materials
however I cant seam to find the structure of some of the materials
(for example Face-Centred Cubic Structure)
I was wondering if anybody here knew any of them:-

-High Carbon Steel
-Copper
-Brass
-PVC
-Polypropylene
-crystalline ceramics
-GRP composite
-Piezo electric materials

It would be much appreciated if anybody could help as i know there is a few engineers on this now and again

thanks

I'm not a materials engineer but Copper is FCC according to wiki... although I think it can exist in other states too.

I think that ceramics will differ depending on what ceramic - google it.

GRP as a whole doesn't have "a" crystalline structure as it's a composite. The matrix will have a different structure to the reinforcement (and not necessarily crystalline). Do you mean the crystalline structure or the larger scale stuff to do with isotropic/anisotropic, weave etc?

Most of the stuff you need to know should be available on google or in materials textbooks. Do you need to know about "structure" in general or the micro or macroscopic structure?

[Martin T]

My googles not working at the moment
which is really anoying
but I think it only wants the crystalline structure,
because in my course notes we have been given it only has FCC and CRH etc.
I just cant seam to find them anywhere.
I musnt be looking in the right place
thankyou anyway

[turbobloke]

You may know much of this already, but you did ask.

Iron is BCC, steel maknig puts carbon atoms in interstitial sites. The term 'martensitic' might be relevant.

Copper is FCC

Not sure about Brass, seem to remember simple cubic in that context but could be wrong.

PVC and polypropylene are thermosoftening plastics with a long-chain molecular structure that will have varying degrees of crystallinity in the polymer depending on the nature of the forming process.

Crystalline ceramics - e.g. silica tetrahedrons and layers?

Composites - matrix and reinforcers? Which composites?!

Piezoelectric material - e.g. wurtzite as HCP?


The question seems to be far too general in places.

[T5SOR]

ONC? I remember the days I will hunt out a superb site I found.

[Martin T]

turbobloke said:

You may know much of this already, but you did ask.

Iron is BCC, steel maknig puts carbon atoms in interstitial sites. The term 'martensitic' might be relevant.

Copper is FCC

Not sure about Brass, seem to remember simple cubic in that context but could be wrong.

PVC and polypropylene are thermosoftening plastics with a long-chain molecular structure that will have varying degrees of crystallinity in the polymer depending on the nature of the forming process.

Crystalline ceramics - e.g. silica tetrahedrons and layers?

Composites - matrix and reinforcers? Which composites?!

Piezoelectric material - e.g. wurtzite as HCP?


The question seems to be far too general in places.

Sorry for the generalisations
But I really have no idea
And I think that the way that the assignment task sheet is set out it doesnt matter.
It's the sheet thats generallising not me,
However GRP stands for 'Glass Reinforced Plastic' so I'm guessing reinforcers
And im not sure about the crystalline ceramics, it says for example aluminuim oxide and beryllium oxide.
but it doesnt state which piezo electric material

[Martin T]

T5SOR said:

ONC? I remember the days I will hunt out a superb site I found.

Thanks

[hairykrishna]

Martin T said:

Hello everybody
I'm just trying to do my assignment for my engineering NVQ on
'Properties and Applications of Engineering Materials'
And I've done the applications and the properties of the materials
however I cant seam to find the structure of some of the materials
(for example Face-Centred Cubic Structure)
I was wondering if anybody here knew any of them:-

-High Carbon Steel
-Copper
-Brass
-PVC
-Polypropylene
-crystalline ceramics
-GRP composite
-Piezo electric materials

It would be much appreciated if anybody could help as i know there is a few engineers on this now and again

thanks

Are you sure you just need simple crystal structure as an answer?

Copper and brass are easy; both are FCC. High carbon steel is BCC but it's properties come from the position of the carbon atoms. I can't remember for PVC; I think it's dependent on a few things, orthorhombic crystals though. Ceramics and Piezo electrics depend on which ceramic/piezo crystal you're talking about. Piezo crystals tend to be quartz like (i.e. trapezohedral). GRP is a composite of glass in some plastic matrix - asking for it's crystal structure doesn't make a lot of sense.

[Martin Keene]

Martin T said:

Hello everybody
I'm just trying to do my assignment for my engineering NVQ on
'Properties and Applications of Engineering Materials'
And I've done the applications and the properties of the materials
however I cant seam to find the structure of some of the materials
(for example Face-Centred Cubic Structure)
I was wondering if anybody here knew any of them:-

-High Carbon Steel
-Copper
-Brass
-PVC
-Polypropylene
-crystalline ceramics
-GRP composite
-Piezo electric materials

It would be much appreciated if anybody could help as i know there is a few engineers on this now and again

thanks

Argh...

I've just been taken back 15 years to Materials 2 on my ONC!!!

Weirdly I never really felt like I got to grips with Materials, hence I'm not even going to try and help because I can't be sure I'm right, but I came top of the year...

[Martin T]

hmmmm :/
well it is worded in the question:-
describe the structure, properties and typical applications for the following materials: etc etc
them ones up there ^^
But I'm not the best at materials either,
Im more the maths and process geek
But I've explained the properties and the applications and even finished the merit questions,
but I just cant seam to get my head round this strucure milarcy

[turbobloke]

hairykrishna said:

Martin T said:

Hello everybody
I'm just trying to do my assignment for my engineering NVQ on
'Properties and Applications of Engineering Materials'
And I've done the applications and the properties of the materials
however I cant seam to find the structure of some of the materials
(for example Face-Centred Cubic Structure)
I was wondering if anybody here knew any of them:-

-High Carbon Steel
-Copper
-Brass
-PVC
-Polypropylene
-crystalline ceramics
-GRP composite
-Piezo electric materials

It would be much appreciated if anybody could help as i know there is a few engineers on this now and again

thanks

Are you sure you just need simple crystal structure as an answer?

Copper and brass are easy; both are FCC. High carbon steel is BCC but it's properties come from the position of the carbon atoms. I can't remember for PVC; I think it's dependent on a few things, orthorhombic crystals though. Ceramics and Piezo electrics depend on which ceramic/piezo crystal you're talking about. Piezo crystals tend to be quartz like (i.e. trapezohedral). GRP is a composite of glass in some plastic matrix - asking for it's crystal structure doesn't make a lot of sense.

Pretty much as posted at 14.25, though as brass is an alloy of copper and zinc in which some atoms in the FCC copper lattice are replaced by zinc, calling the result FCC needs a degree of licence.

[hairykrishna]

Martin T said:

It's the sheet thats generallising not me,
However GRP stands for 'Glass Reinforced Plastic' so I'm guessing reinforcers
And im not sure about the crystalline ceramics, it says for example aluminuim oxide and beryllium oxide.
but it doesnt state which piezo electric material

Well, beryllium oxide is HCP at sensible temperatures. Al oxide depends on the phase.

[turbobloke]

hairykrishna said:

Martin T said:

It's the sheet thats generallising not me,
However GRP stands for 'Glass Reinforced Plastic' so I'm guessing reinforcers
And im not sure about the crystalline ceramics, it says for example aluminuim oxide and beryllium oxide.
but it doesnt state which piezo electric material

Well, beryllium oxide is HCP at sensible temperatures. Al oxide depends on the phase.

Which all goes to make you wonder about the people setting the assignment(s).

[hairykrishna]

turbobloke said:

Pretty much as posted at 14.25, though as brass is an alloy of copper and zinc in which some atoms in the FCC copper lattice are replaced by zinc, calling the result FCC needs a degree of licence.

Yeah, missed that reply, sorry. As the question seems to be requiring gross generalisations I though the brass answer was reasonable!

[stuthemong]

Martin,

Hairykrishna seems to talk a lot of sense - esp the GRP composite answer.

If you wanted to really show off you could mention the Ashby&jones material selection charts (here http://www.grantadesign.com/ashbycharts.htm ) to show you which materials are best for an application.

There are different charts for thermal expansion/YM/strenght/cost/recyclability now, and a engineer may well use these charts to decide which material is best for a given design constraint. I daresay that if you mentioned these under the eng. materials properties heading it should be worth some decent bonus points..... although...... as said by other posters here, judging by the way the questions are posed, there is a danger the marker won't have heard of these charts :s

Edited by stuthemong on Sunday 7th December 15:02

[hairykrishna]

Martin T said:

hmmmm :/
well it is worded in the question:-
describe the structure, properties and typical applications for the following materials: etc etc

Ok. Sounds to me like it's asking for an actual description of general structure and what influence that has on properties rather than just 'what is the crystal structure'. Makes a lot more sense.

[Martin T]

hairykrishna said:

Martin T said:

hmmmm :/
well it is worded in the question:-
describe the structure, properties and typical applications for the following materials: etc etc

Ok. Sounds to me like it's asking for an actual description of general structure and what influence that has on properties rather than just 'what is the crystal structure'. Makes a lot more sense.

OK sorry,
It was me generalising then :/
I didnt realise,