I already posted this question 2rd time now someone didn\'t answer the whole thi

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I already posted this question 2rd time now someone didn't answer the whole thing this is a 2rd refund please just answer all parts:

You are required to answer all parts of the question. Our professor gave it as you see it as a single question, so to save time getting a refund and posting again just please.

I know the rule is 1 question at a time in material science at our university this is a single question!!

And correctly clear writting please.

it would be a pain for me to separate them, since I have a fair bit of them.

And finally please do not write on a piece of paper then take a single photo with your mobile phone its going to be blured we can't see it use a photo copier. otherwise take multiple close up photos if mobile is all you have.

7. answer all parts A B C

a) Explain how titanium alloys are classified and describe what the effect of the major alloying elements is. (4 marks) b) Please describe three forms of localised corrosion specifying in which types of applications and/or materials/environments is more likely to happen. Also describe two mechanisms to protect materials from corrosion. marks c) AAS an engineer, you arc presented with an Ellingham diagram (Figure 1 and asked to list the following metals CAi, Cr. Ti, MM g and Fe) in order of increasing oxidation resistance. Moreover, you ure asked to justify why metals such as Al and Ti have a high oxidation resistance while their oxidation tendency is high? (5 marks) k 00. T C C

Explanation / Answer

solution-1)

Titanium alloy are the metals which contains the mixtures of pure titanium metals and other chemical elements or protective metals. by combining these two mixtures in a suitable ratio, we produce the alloy called "titaniuam alloy". alloys are basically known as the homogeneous mixture of two or more different metals by fusing together. titanium alloys are having high tensile strength and toughness.they are light weight and having corrosion resistances.

Titanium alloys are classified as under four categories as-

1) alpha alloy- these alloys pf titanium contains the neutral alloys elements such as tin or aluminium and these are not heat treatable.

2) near alpha alloy- these contains small amount of ductile beta phase .they are alloyed with 1-2% of beta phase stabalizers such as silicon.

3) alpha and beta alloys- these are metastable and generally includes some combinations of both alpha and beta stabalizers and these are heat treatable.

4) beta or near beta alloys- these are metastable and contains sufficient beta stabalizers to allowed them to maintain the beta phase during the process of quenching.

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solution-2)

Localized corrosion can be defined as the selective removal of metal by corrosion at small areas or zone on a metal surface in contact with the corrosive environment or medium such as liquid water. it takes place when the metals is subjected to interect certain mechanical activities like stress, strain and fetigue. it is the most dangerous type of corrosion which start at point area and engulf the whole metal objects.

three forms of localized corrosions are as -

1) pitting corrosions- it is a type of localized corrosion in which holes are produce in the material. the driving power for this types of corrosion take place as the small surface area acts as anode while large surface area acts as cathode which result in the formation of a potential difference and initiate the pitting localized corrosions.

2) stress corrosion cracking- it is the growth of crack formations in the metal surface when it subjected to any elevated temperature. this is a type of localized corrosions.it produces sudden failure of a ductile metals when subjected to tensile stress.

3) crevice corrosions- it is a type of localized corrosion in which it is refers to the localized attacks on a metal surface at or immediately adjacent to gap or space between two joints. the gaps may be in between metals-metals or it may be metal-nonmetals.

mechanism to protect metals from the corrosions are as-

1) conditioning of metals- it can be defined as the modification of the metals according to the working situations, conditions and environment. in this , it include designing properly, select the proper metals before manufacturing the objects, passivations and prevention by the help of coating.

2) conditioning of the environment- it can be refers to as the modification of the working atmosphere according to the work and machine activities. it may be happens by using some inhibitors and by modifying the environments

3) electrochemical controls- it is also refers as the protection of the metals by using the concept of electric potential. as we know that for the corrosion to take place it is necessary to establish both cathodic as well as anodic state together. to stop corrosion by this method, we make the metals which we have to protect is more cathdic to the sacrfice metals. by doing so we can protect the desire metals very easily.

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solution-3)

According to the fact that we know is that both the aluminium as well as titanium have the high affinity towards the oxygen but they have high resistance to corrosion because when these metals are subjected to interect with oxygen, initial they form oxide by reacting with oxygen but after a certain time these oxide layer seem to be act like a protective layers on the surface of metals. this protective oxide layers passivate the further reaction with atmospheric oxygen and hence stop the further contact and reaction with oxygen. hence these metals have high oxidation resistance.

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