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Structural Alloys for Energy and Transport - Part 4

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Structural Alloys for Energy and Transport - Part 4

This module illustrates several applications of HTMD covering a range of material classes, properties, industrial sectors, and maturity levels.

Introduction to High-Throughput Materials Development

Instituto de Tecnologia da GeórgiaInstituto de Tecnologia da Geórgia

This course is an introduction to high-throughput experimental methods that accelerate the discovery and development of new materials. It is well recognized that the discovery of new materials is the key to solving many technological problems faced by industry and society. These problems include energy production and utilization, carbon capture, tissue engineering, and sustainable materials production, among many others. This course will introduce the learner to a remarkable new approach to materials discovery and characterization: high-throughput materials development (HTMD). Engineers and scientists working in industry, academic or government will benefit from this course by developing an understanding of how to apply one element of HTMD, high-throughput experimental methods, to real-world materials discovery and characterization problems. Internationally leading faculty experts will provide a historical perspective on HTMD, describe preparation of ‘library’ samples that cover hundreds or thousands of compositions, explain techniques for characterizing the library to determine the structure and various properties including optical, electronic, mechanical, chemical, thermal, and others. Case studies in energy, transportation, and biotechnology are provided to illustrate methodologies for metals, ceramics, polymers and composites. The Georgia Tech Institute for Materials (IMat) developed this course in order to introduce a broad audience to the essential elements of the Materials Genome Initiative. Other courses will be offered by Georgia Tech through Coursera to concentrate on integrating (i) high-throughput experimentation with (ii) modeling and simulation and (iii) materials data sciences and informatics. After completing this course, learners will be able to • Identify key events in the development of High-Throughput Materials Development (HTMD) • Communicate the benefits of HTMDwithin your organization. • Explain what is meant by high throughput methods (both computational and experimental), and their merits for materials discovery/development. • Summarize the principles and methods of high throughput creation/processing of material libraries (samples that contain 100s to 1000s of smaller samples). • State the principles and methods for high-throughput characterization of structure. • State the principles and methods for high throughput property measurements. • Identify when high-throughput screening (HTS) will be valuable to a materials discovery effort. • Select an appropriate HTS method for a property measurement of interest. • Identify companies and organizations working in this field and use this knowledge to select appropriate partners for design and implementation of HTS efforts. • Apply principles of experimental design, library synthesis and screening to solve a materials design challenge. • Conceive complete high-throughput strategies to obtain processing-structure-property (PSP) relationships for materials design and discovery.

Visualizar o programa do curso

Ministrado por

Dr. Richard W. Neu
Professor
Dr. J. Carson Meredith
Professor, Associate Chair for Graduate Studies, and J. Carl Pirkle Sr. Faculty Fellow

Transcrição

[SOUND] Hi, I'm Ric Neu, in this lesson,

we'll continue our case study on structure

alloys for energy and transport.

In this lesson, we'll focus on the next steps of alloy library synthesis and

characterization.

The learning objective is to describe the next steps of synthesis

of alloy libraries and high-throughput experimental characterization and

property measurements.

So this involves step three and four.

So step three, I broke it up into 2 parts, step 3a and step 3b.

Step 3a being the synthesis of the library,

in this case with the composition gradient.

And we'll see step 3b will be then the characterization of that library.

So how can libraries be prepared?

Well, we look back at our previous modules and

realize libraries can be prepared through thin film vapor deposition methods,

added a manufacturing, diffusion multiples.

The challenge here is though the creates samples with five or

more elements and conceivably it could be done.

But it may requires some creativeness in creating these libraries,

but there's nothing technically that a shows stop are here.

For example, you could take wedge arrays of diffusion multiples to create several

compositions on the same sample.

Step 3b involves the characterization.

And again, we go back to the previous module on characterization and

property measurement and explore what approaches may be appropriate for alloys.

For example, understanding what phases are present, are important so

we measure those things by Electron Probe Micro-Analysis,

Energy Dispersive Spectroscopy, X-ray Fluorescence,

EBSD, Electron Backscatter Diffraction can even give the crystal structure.

And based transformations may be import.

Base transformations that occur during say the cooling, so

Differential Thermal Analysis methods or High-throughput nano-calorimetry.

So there's other types of methods who are interested in how the resistance changes

with a transformation so temperature dependent resistivity measurements.

Now, we're dealing with high temperature alloys so

oxidation resistance by exposing the library to air at the use temperature

might be important to see what sort of reactions occur in that environment.

We can do the elastic modulus by nanoindentation.

Elastic modulus tense to be a composition depend in properties so

that would be a proper here.

And we can do look at strength by nanoindentation in micro-pillar

compression test perhaps.

Those strength depends on the microstructure, too.

So we might not have an optimum strength at this time but

it might give us senses to which alloys we might want to screen out at this point.

So let's remind ourselves of the processing structure property chart,

and keep in mind that we've completely missed this part so far.

We've only focused on composition and solidification.

We haven't looked at any thermal mechanical processing,

hot working which includes hot forging, hot rolling,

cold working, and we haven't even considered solution treatments and aging.

And we know that those are all important for predicting the strength,

toughness properties which are critical for the alloys we're considering.

So we need to go Step 4.

Develop alloys with microstructure gradient.

And so, for the down-selected composition of alloying elements

we got from step three, now we probably pick one and

generate a library with a microstructure gradient.

And we can do this by hot or cold working, via upset forging or rolling.

We saw those in previous lessons.

We could have a gradient in a quench rate and we could look

at different solution treatment and aging processes and there's multiple of them.

And for two phase alloys, the size, volume fraction and distribution of

the precipitates are controlled by these solution treatment and aging parameters.

Including solution temperature, quench rate, aging temperature, and aging time.

And so, we need a sample with a microstructure gradient

perhaps made either by deformation processing or with the thermal gradient.

And you can see the role of those would be both important for this alloy development.

And then Step 4b would evaluate microstructure dependent properties

using these high-throughput methods.

So now we're looking at really strength,

properties that are dependent on the microstructure.

So strength by nanoindentention using spherical indenters which

tells you something about the modulus, the yield and the harding behaviour.

You could also look at micro-pillar compression test, and there are some other

methods, but those are probably the two easiest ones to consider.

Fracture toughness is important for these alloys.

You have to have a tough alloy.

And that's a hard one to get a grasp of, that property

with high-through put methods, but you can get an indication of fracture toughness

through the micro-pillar defamation behavior, so you look at how it deforms.

Does it brittley deform under compression or does it shear very nicely and

look more like a plastic deformation mechanism.

Or you could use nanoindentation with sharp indentors.

Which if it's too brittle or has too low of a fracture toughness, you'll form

cracks at the tips of the sharp part of the indentor in the material.

And again, we need to look at oxidation resistance by exposing library to air.

Because the microstructure will play a role in the oxidation resistance because

of the sum of the segregation that occurs in the elements.

And so, now you'll have a very small subset of alloy composition and

possible process routes that you can explore further.

So Step 5 is focus your resources.

This is the most expensive part, on developing alloys with

the greatest potential that you've screened out from steps one through four.

And so, the lesson summary here is we've described

the next steps of synthesis of alloy libraries and

high-throughput experimental characterization in property measurements.

And so, overall, the process involves really three key steps.

The three middle steps are the most important ones

with regard to high-throughput.

Step 2 being the computational methods and there the least accuracy is okay.

To just screen out the ones that won't work.

Step 3 is now when we start experiments so the high-throughput experiments we

need a little bit more accuracy in the measurements of the phases.

The property measurements.

And then, Step 4 where we're looking at microstructure gradients perhaps

even a little bit more accuracy so we can get to that Step 5.

So this comes to the end of this particular case study.

So what is the future of alloy design?

And this chart illustrates it fairly, fairly well.

Steel has been around for over a century, yet,

using high-throughput materials development, it will facilitate

the discovery and design of new, strong, tough, corrosion resistant steels.

And in fact, just some recent work in this area suggests that we can

design a steel that has higher strength and higher toughness, higher ductility.

And probably better corrosion resistance than we currently have today,

even some of the more advanced high-strength steels.

So the opportunities are there.

Thank you.

[SOUND]

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