Author : Piyush Raj
In my limited time as a student in Mechanical Engineering, I am yet to meet an undergraduate who has publically or in closed group have proclaimed that he/she wants to pursue Material Science in future and is passionate about this field. The reluctance for picking up Metallurgy and Material Science is so high in our country that people are willing to sacrifice an year after competitive examination even if they secure a seat in the most reputed college in the country.
The disinterest in the subject is many a times obvious with the subject having less impact on day to day life of people and lesser rewards it offers to the people in the industry but that is not the case with Material Science. If you look around yourself, there’s not a thing that you’ll find where the contributions of Metallurgists isn’t significant.
Materials are probably more deep-seated in our culture than most of us realize. Transportation, housing, clothing, communication, recreation, and food production — virtually every segment of our everyday lives is influenced to one degree or another by materials. Historically, the development and advancement of societies have been intimately tied to the members’ ability to produce and manipulate materials to fill their needs. In fact, early civilizations have been designated by the level of their materials development (Stone Age, Bronze Age, Iron Age) — the opening lines of the textbook on Material Science by William D. Callister.
The first designation to the era where flora and fauna existed is that of Ice Age (a term which is more close to Geography) but after that we have everything contributed to materials. The current time which we most often call as Information Age exists because of the advent of Silicon Chips (Semi-conductor) and our ability to manipulate materials down to atomic level. Yet, the young doesn’t pick up Material Science enthusiastically.
I have been studying the subject lately and seeing how wide implication this subject holds ( I realized this only after working in the workshop where knowing the technicality behind the materials you are working with needs to be as par with the knowledge of how and when it is to be done), I feel an urge to bring some spark to this subject, which is as old as human civilization itself and perhaps that is why it is suffering from erectile dysfunction at this age.
How do you do that?
The answer is: Make it Put on a Bra.
We will begin with the very basic concept:The Hooke’s Law
And the famous curve is as follows:
Why to think of Bra when you look at the curve?
When you try to unhook it, you need to apply a threshold force to take it off, otherwise, it goes back to being the way it was. Materials exhibit the same property within the Elastic Limit.
Note that the Elastic Limit is defined as the region in which if the material is in, it can regain its original shape and size provided the external forces are removed from it. The material may not follow the Hooke’s Law (proportionality of stress and strain) and still be Elastic.
After the material has yielded, the strain hardening occurs. Well, after you remove the bra completely, something hardens beyond repair. I’ll leave this to reader’s imagination.The Phase Diagrams
One of my teacher began the lesson on Phase Diagrams in a very interesting way. He asked, “I have a material A and material B. If I make an alloy AB, what will be the strength of the material ?”
“It will be greater than the individual strength of A and B”, the class shouted as everyone was aware that alloying increases strength.
“What will happen to the Melting Point”, he asked after that.
The class no longer unanimously proclaimed a single answer. He then went on describing that we cannot comment on Melting Point directly. In order to find the Melting Point, we need to look at Phase Diagrams of the material and that is something that we get from the experiment. The variations in melting point of alloy and mixed materials is so much that at a particular composition, the melting point lies in a range than a single temperature unlike Pure Substances.
The Academic discussion begins with describing Binary Phase of Type I (complete solubility of two materials in one another) but since, I have to develop an analogy, I’ll begin with Binary Phase of Type II (the one which has partial solubility)
At the first sight, the diagram looks very complex.
Let me make it simple for you.
I have received complaints from my peers saying that the original curve is unsymmetrical and the bras are epitome of symmetricness. To them, I have nothing but to quote the natural fact that the thing what this garment supports are not symmetrical. They went for Google Search to verify and thanked me later.
Now if you see a plot for Binary Phase Diagram of Type I (complete solubility, you get the following
One can easily deduce that this is like a small part of the previous curve.
Now, we move to the perhaps the most important curve that is there in the Material Science.
The Iron-Carbon Diagram:
Now all of it must have made you think that I am perhaps the creepiest guy that has ever walked on Earth. Well, talking of Creepiness, let’s talk of creep as well.Creep
Creep is a time dependent permanent deformation of materials under constant load or stress. The phenomena is more pronounced at 0.4 times the melting temperature of material, hence the term recrystallization temperature is also added to its definition by some experts.
If I tell you that the curve resembles the curvature of the cup shape of the garment, you will discard the logic by telling that I am deliberately trying to relate things but let us look at several creep curves with varying temperature.
Variation of Creep Curve with temperature, where T stands for Temperature and the subscript ‘m’ refers to Melting Point and the numerals in the subscript represents different temperature points. Sigma stands for Stress. [Courtesy: Material Science and Engineering: An Introduction by William D. Callister]
Now see the following curve:
My small research on the topic not only strengthened my concepts on Material Science but also made me develop a little interest in the subject. I came to know that there’s a field of Technology known as “Bra Engineering” which by now has enough resource available that one might pick it up as an engineering specialization.
And for all the women out there, I feel for you people, the suffering that you go through because of wrong size and illiteracy and taboo that surrounds in discussing these things.
Nevertheless, Happy Learning