Designing and developing new materials is through something that
we refer to as a materials design paradigm,
and that paradigm is made up of first the structure.
And when we think about structure there are variety of
levels that we must consider.
We must think about the atomic level where we're dealing with individual atoms and
collections of atoms, the nano level, the micro level, and the macro level.
As we go from left to right, we're going to different scales in
the length of the material and that becomes very important.
So one of the descriptors that we use in materials design is the length scale.
Of course we're interested ultimately in the properties of a material.
We can measure these properties, there are variety of them that we had
already considered, certainly there are mechanical properties.
There are various physical properties that include electrical, magnetic and optical.
And another type of property we refer to as chemical, and
that chemical can be the interaction with the material and its environment.
In addition to altering the properties of a material and
changing the structure of the material by composition, we can also do it by process.
This is referred to as the materials history.
How was the material fabricated?
How was it cast?
How was it processed, and then ultimately how was it produced in a final shape?
And ultimately, we're interested in the performance.
How good is that material
that we're using in service in a particular engineering application?
To help address these individual points, the material engineer
looks at something that we refer to as the tetrahedral jacket.
If we take each one of those triangles and bring them together,
we'll form a tetrahedron, but I've spread them out and I'm emphasizing here
that ultimately, performance is something that we're very very interested in for
us to use new materials.
But the structure, the properties and the process, are all important,
they're all interrelated to one another, and
ultimately they wind up controlling the performance of the material.
This ends our discussion on the materials design paradigm.
In the next lesson, we're going to be talking about how do we
develop a particular material for an application that's been around?