MATERIALS SCIENCE AND
ENGINEERING
Tracing a path from India
to the United Kingdom to the United States of America, the author shares his
insights about new materials such as graphene and techniques such as
3D-printing.
 |
| Prof. Suresh Babu |
Introduction
Thirty years after
graduating from the PSG College of Technology and looking back, I am humbled by
our teachers’ passion and am realizing the real meaning of the kriti, “Endharo
mahavubhavulu, andhariki vandhanumu,” composed by Saint
Tyagaraja. In the same spirit, I salute the great teachers and
scientists, as well as, my friends who have inspired me to pursue the world of
materials science.
This chapter provides an
overview of progress and future direction of shaping the materials in the last
thirty years from my viewpoint. I hope these anecdotes and thin
slices of experiences strengthen the creativity and grit of future students.
The
direction of pursuit is cast
On a hot summer afternoon
thirty years back, the train named Kovai express was making its usual last lap
of the journey, its wheels hugging the steel rails near the Peelamedu -
Avarampalyam curve. I looked out through my window with
trepidation of my future at the PSG College of Technology. On either
side of the tracks, I saw lot of small factories with tubular furnaces among
grey sand piles.
I turned around asked my
brother-in-law, who was traveling with me, what these were. He looked at me
with pride, and said that those are cupola furnaces in
foundries, the economic engine of Coimbatore. With beaming eyes, he further
explained that they make parts that go into all other machines, which are used
by other business sectors, including textiles, another big sector in the city
of Coimbatore. Somehow, as the air with burnt iron fragrance
enveloped me, I knew that my life was cast in the materials
world.
As the time at college
moved on and we made friends, as we learned about engineering tools, to design
parts, melt metals, make molds for castings, blacksmithing, machining, and
welding, our tapestry of life was unfolding right in front of us.
Like a
cooking recipe
While at college, a
technician in-charge of melting furnace at PSG College of Technology foundry
greatly influenced me. All day long, he would take a scoop of molten metal cast
it into a disc shape. He would put that disc in a pneumatic
tube. Magically, it would be transported to another part of the
building. Then, he would wait for a phone call for a report that
helped him to make the decision to pour or not to pour the molten metal into
casting.
I approached this man and
asked him, what he was doing. He looked at me said, “hey kid, this
is like cooking, if your ingredients are not in proper ratio, your food will be
bad.”
If the molten material was
not in the right composition, all the castings would be junk and the foundry
will lose lot of money. I could see his passion, pride and commitment
to his job.
Reluctantly, not hiding my
lack of knowledge, I asked what was at the end of that tube. He said
there is a lab, which checks the recipe. He followed with an
authoritative voice in Tamil: “Book knowledge can only take you half
the way; to scale the whole mountain, you need to have the practical knowledge
of using ropes and ladders.”
Question
and Answer
With my friends Sundar and
Subbu, I made the trek to the laboratory and found the plasma spark analysis
instrument. That machine took those discs and evaporated the constituents into
a vapor and measured the relative concentration of silicon, chromium,
molybdenum, nickel and iron.
Again with reluctance, I
asked why these recipes were important for the casting. The lab manager looked
at us with a weird look and said, ‘you
are wasting my time, you should have learnt it from NKS.’
NKS, aka., Professor N. K.
Srinvasan taught us physical metallurgy. In one of the
lectures, while he was talking about dislocations and its impact on properties,
he articulated, with a glitter in his eyes, his research experience pertaining
to semiconductor materials at Columbia University, in New York in
the United States of America. I was convinced, at that moment, he was not in
that classroom; he had time-transported himself to his past to a lab in
Columbia.
This was the moment I
realized there is a fun in asking questions, “why, what, when and how -
related to materials world,” and can also build one's career answering the
questions.
Pursuit
of stronger materials
(aka
the Complex life of Fe and C atoms)
I was a fan of comic books
when I was growing up. I used to wait at the street corner shop for
my favorite “Irumbukai Mayavi” published by Muthu
Comics. This is based on British superhero, who has an artificial
hand. On plugging his hand into A/C circuit, he goes through extreme pain and
gets charged up, and becomes invisible. At the same time, I used to
hear about another superhero “Iron Man,” published by Marvel
Comics too.
I always wondered when I
would get this magical iron claw that can drive off the demons that used to
haunt me after my father passed away. The mystical material iron
really fascinated me.
In my 2nd year, at
college, most of us were really taken aback by the statement by Professor
Ramakrishnan: “you can take pure iron and bend it with your hand. But
on addition of small quantities of pixie-dust, you can make it stronger. Do you
know what that pixie-dust is?”
He went on to explain us
the role of carbon and the background to steel and how it plays its complicated
dance of being close to iron atom at high temperature and heating the iron atom
at low temperature, due to the duality of iron atoms in arranging themselves in
space, explained by crystal structures.
In preparation for being
metallurgical engineers, we studied the ELBS books on Physical metallurgy by
Avner and Mechanical metallurgy by Dieter. We memorized the cooking recipes to make wide range of
steels. We would get confused by
different names given to arrangement of crystals and phases after people like
Austen, Marten and Bain.
A question always remained
in our minds, why are humans blessed with this magical recipe of Iron and
Carbon which allows us build huge skyscrapers like Eiffel Tower, Empire State
Building, cars like Ambassador and other engineering marvels?
Onwards
to Cambridge University
The answer was in lots of
textbooks and papers. But it is nothing
like hearing it from a passionate researcher of steel. Dr. Harry Bhadeshia had moved to the United
Kingdom as an immigrant from Kenya. On arrival at Cambridge, while I
was being frustrated with my inability to understand complex equations and
theories of steels thrown at me, Harry asked me to join him for a nice lunch at
Darwin College.
As we walked and talked
about everything in life, I asked him how he became smarter with all these
equations. He paused for a moment and said, there is no short cut; you needed
to work hard, understand each sentence you read and most importantly you should
visualize in your mind the concepts.
Then, I asked him how he
came up with the theory of bainite transformation. He told me that with his
usual stock phrase, “Look, Suresh! We all stand on the shoulders of
masters.” He went on further and showed his collaboration with
Prof. Jack Christian from Oxford, who had proposed this possibility before
him. He just took it to the completion
with emerging computational tools and characterization.
I can see that Harry will
never stop until he makes the best steels known to us by manipulating the
arrangement of carbon atoms in iron lattice so that they are cheaper, formable,
high-temperature resistant, weldable, and wear resistant. Well, even
now he is continuing this journey with so many.
Suddenly, I realized that
scientists are not born; they evolve from simple humans by asking
questions Why? When? What? How? work hard and keep trying
until they reach the end of the rabbit hole and keep digging.” That
means a student, including the one who is walking on Avinashi road in Coimbatore can be a scientist, the degree you
receive is just a driving license to do research!
Innovation
In 2005, while attending a
steel conference at a monastery in Kyoto, Japan, a young entrepreneur, Gary
Cola, approached me, “I have made steel stronger in 30 millisecond
better than anyone in the world, are you interested in working with me?”
Usually, faculty who are
engrained in pedagogy would dismiss him. However, I remember what Harry taught
me, be mindful of innovation and creativity lurking around the corner,
irrespective of degrees you hold. This was the most challenging and exciting
part of research my students and I did, where we discovered how Gary’s process
works and how we can join them too.
Interestingly, we live in
the world, where carbon alone wants to rule the world without the iron, i.e.,
discovery of graphene, which is claimed to be 100 times stronger
than steel. Now, I wonder whether this divorce of iron and carbon
will lead to better world in the long run?
I hypothesize that we will
continue to make stronger and better and cheaper steels for macro world in
which iron and carbon will live happily together in FCC crystal structure and hating each other in BCC crystal structure from time to time. At the same
time, a nano-world will emerge where iron and carbon atoms may go on their
separate way to create exciting electro-magnetic devices!
Now, you may wonder, do we
have a way to create meta-materials that may bend the light and make us vanish
and be stronger, like irumbukai mayavi and Harry
Potter
Remember that the answer
lies around us. Thus we need to ask the
question and persistently search for an answer.
I
suggest that we should not wait to get a driving license to conduct
research; we should ask the why, what, how questions now.
Pursuit
of stronger bonding between materials (and peoples)
One of the questions of
life in real world we face is following: how can we address challenges that are
far bigger than an individual can make it happen?
I remember as a kid
watching the movie Pallandu Vazhga, with lead role by the
legendary MGR. In this movie, as a jail warden, he takes up the challenge of
rehabilitating six inmates. The warden's motivation is questioned by
everyone, asking that how helping six inmates going to make a difference to the
whole country. In a clever, but relevant, demonstration is done in
the movie. He draws a figure of a human behind a map of India. Then
he tears the map, and shuffles and asks his audience to arrange it using the
map-face side of the paper. All of them have trouble in fixing them. All of
them are frustrated to certain extent, at that time, he asks them to turn the
map around and arrange the human figure. All of them can do it very easily.
When the paper is flipped, the audiences get the whole map of
India.
This can be a metaphor to
translate into the materials world. In the late 1980s, an engineer
named Wayne Thomas from The Welding Institute was working on
solid-state welding of metals and alloys. One day, he had a brilliant
idea that if we can use a rotating and moving hard tool that can plasticize
metals in the solid state and interpenetrate them by cross flow, we can make
large-scale solid-state joined structures. He postulated that it
could be used for joining high strength aluminum alloys used by aerospace
industries, which are very difficult to join by fusion welding processes.
No one took his idea
seriously.
However, he did not listen
to the naysayers, since he was confident that his idea would work. He independently
worked and developed this technology called Friction Stir Welding.
Now this technology used by many industrial sectors, including the
upcoming space launch system. This clearly shows one
man’s grit can indeed bring the material world together.
This story made me to
devote my career to the challenging world of joining materials in three
dimensions including the emerging technology referred as additive
manufacturing, also known as 3D printing.
Summary
The world of new materials
is emerging with bridges being made between organic and inorganic materials
with their unique properties. We need to design hybrid materials with form and
functions by shaping them similar to nature while dealing with diversity and
heterogeneity of their properties for betterment of society around
us. In Mahatma Gandhi’s words, we should aspire to “be the change
that you wish to see in the (material) world.”
About the author:
Prof. Suresh Babu obtained his
bachelors degree in metallurgical engineering from PSG College of Technology
and his master’s degree in industrial welding metallurgy from Indian Institute of Technology, Chennai.
He has a PhD in materials science and metallurgy from University of Cambridge,
UK. He currently occupies the UT/ORNL
Governor's Chair of Advanced Manufacturing at the College of Engineering at the
University of Tennessee in Knoxville, TN.
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