From Edison’s Desk: Blog of the GE Global Research Center

Here, with posts written by GE researchers working on all kinds of interesting things. Given the central role of materials in many of the advanced technologies being developed by GE researchers, the blog has quite a few posts that touch upon materials science and engineering.

Take, for example, the latest post by Greg Gorman and Dan Dunn. It’s on the development of ceramic matrix composites (CMC) that use SiC fibres within a SiC matrix! After discussing the background about why GE’s intereste in this kind of materials (their potential use in turbines), it summarizes the reasons for developing CMCs, as opposed to monolithic ceramic materials — the latter fail in an utterly brittle fashion. What makes the post truly special is the visual evidence — videos of bullets hitting these materials at a velocity of 150 miles per hour!

It’s always great to see materials engineering in action!

Before closing, I should point you all to Suchismita Sanyal, an alumna of our Department, and a researcher at John F. Welch Technology Centre (GE’s research lab in India), Bangalore. Here’s an extract from her post (from a while ago): Power of Atoms:

Here we have taken a Pure Nickel grain boundary, as a starting point, as Ni forms the most common base metal for the high temperature superalloys used in jet engines. Of course it has a whole lot of other additions to it, but, one step at a time …..

We have added lot of elements (as dopants) to the grain boundary to inspect their effects on the “Cleavage Energy,” which is the energy to pull two grains apart, along the grain boundary. In presence of the dopant, if we need to put in more energy than in the pure case to cleave the grains, the grain boundary is stronger, and vice versa!

Our calculations show that by putting Sulfur, the cleavage energy of Ni-S goes down compared to pure Ni case. The physical implication is then that S weakens Ni grain boundaries. How about Boron? Boron is experimentally known to be a grain boundary strengthener, and voila! What do our calculations teach us? That Boron addition to grain boundary actually raises the cleavage energy values than the pure Ni grain boundary, hence strengthening it! Well, isn’t it fun, to see our calculations validating long-known experimental facts? We are now exploring role of newer dopants, and I will share those stories soon!

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About Abi

My name is T. A. Abinandanan, and I am a professor of Materials Engineering at the Indian Institute of Science, Bangalore.
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