Engineering Material Selection help!!!

[sootydaz]

Firstly, Thanks to anyone who takes the time to try and help me, as i am aware there are people all over the world who are far more intelligent than myself so here goes with my question

 

I have 3 unknown materials which i have to name X,Y and Z and 3 graphs from which i have deduced the Young's Modulus of Elasticity for each material.

 

 

X= 161.29 GPa (GigaPascals) I think maybe Manganese (Mn)

 

Y= 277.8 GPa (GigaPascals) I think maybe Tungsten Alloy

 

Z= 600 Pa (Pascals) NO IDEA.

 

I have scoured the internet and i have had some success but i do not know if i am right so i was hoping for some guidance in the right direction, Maybe a reference ?

 

 

Once again many thanks in advance

 

Daz

[Hal.]

sootydaz , Keep in mind that the properties of a material can change a lot with an increase or decrease in temperature .

 

Young's Modulus of Elasticity is denoted by the letter E . I am assuming that these materials are metallic .

 

Your question is a bit like trying to identify a car by how fast it is travelling down the road . Lot's of cars have the same speed and so speed on it's own can't be used as a way of identifying the particular car .

 

Material X has an E = 161.29GPa . An alloy of Copper 86 % , Manganese 12 % , Nickel 2 % can have an E = 159GPa .

Manganese can have an E = 200GPa .

 

Material Y has an E = 277.8GPa . An alloy of Tungsten 90 % , Nickel 6 % , Copper 4 % can have an E = 276GPa .

Tungsten can have an E = 411GPa .

 

Material Z has an E = 600Pa . That's extremely stretchy and an example of such a material is not easy to find if it even exists at room temperature .

 

If this is a typographical error and you actually meant an E = 600GPa then an alloy of Tungsten 94 % , Cobalt 6 % can have an E = 600GPa .

 

Hal_2011

Edited April 11, 2011 by hal_2011

[sootydaz]

Thanks Hal,

 

I have attached a copy of all the information i have been given with reference to this task, i have completed all parts of the task i.e. drawn the graphs and obtained the young's modulus from the graphs giving me the figures.

 

X= 161.29 GPa (GigaPascals)

 

Y= 277.8 GPa (GigaPascals)

 

Z= 600 Pa (Pascals)

I assume the materials are metallic and i was given a huge hint when begged (probably should have mentioned it earlier) as to the figures i should be expecting to see from my graphs

 

X should be 100-200 GPa

 

Y Should be 200-300 GPa

 

Z Should be 500-700 Pa

 

When i enquired further as i am finding the identification almost impossible i was told 'just find the closest material' provided i can back it up with the relevant references.

 

The identification you have already helped me with is a huge help but do you know where i can reference these figures

 

Thanks

 

now I've actually attached the file might work better.

The Tensile Test.doc

[Hal.]

sootydaz , I think that you have the impression that there are 3 materials that give these statistics and you must find them . You won't . There are a huge number of materials being made by manufacturers and different material contents can give the same properties . That is why you are being told that it doesn't matter what you decide on , once you give references . There is no specific solution .

 

I think your first Modulus of Elasticity for material X is a bit low at 161 GPa . I adjusted for an instrument error I think may be present and I get 200 GPa .

 

For the second Modulus of Elasticity of material Y you give 278 GPa . I did the same adjustment and got 289 GPa . Ask the person you are doing the assignment for , to explain to you what effect on your graphs measuring instrument errors will have and what you should do to make an adjustment .

 

I'll just say that if you look at data from steel makers you will find suitable materials there . Where you look is your decision in the world of cyberspace . Take into account all the properties you are being asked to calculate .

 

Material Z is strange . You can't get the same information about it from calculating as about the other two . I decided on a figure of 947 Pa for the Modulus of Elasticity . This is not an exact science . Where you take your stresses and strains is always going to be approximate . The material is very stretchy and weak relative to steel .

 

20 years ago the internet didn't exist in the form it does today . When people wanted information about materials they had to go to a factory and talk to the people or use the telephone or make a request in a letter using the postal system .

 

Hal_2011

Edited April 11, 2011 by hal_2011

[Newbies_Kid]

I think you can't rely too much on your elastic modulus graph unless you've confirmed that those materials are pure. Alloys can have a variety of strength as the value is dependent on the alloying elements. If any unknown materials can easily be characterized by referring to its tensile properties therefore there is no longer need for materials scientist to rely on complex characterization method such as powder diffraction files, electron energy loss spectroscopy, energy dispersive spectroscopy, glow dispersive spectrum etc..

[baxtrom]

sootydaz,

are you sure the stress levels for material Z is not in MPa?

From the data in the table it looks like a ductile material. If the data is in MPa it could perhaps be some polymer.