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May-June 2015

Volume 103, Number 3
Page 165

DOI: 10.1511/2015.114.165

To the Editors:

I read Lee Langston’s column (“Each Blade a Single Crystal,” January–February, Technologue) with interest. Had the early researchers of these crystals realized that they may have saved some development time by “walking down the hall” and talking with a geologist–structural mineralogist about properties of aggregates and crystals and how to grow large crystals? There are odd environments where crystals grow to multiple tons. Then again, geologists may not have helped much—most of us in mineralogy are focused on the structures and growth of natural silicate compounds, not on metallic alloys. The progression from granular to oriented crystals to single crystals that you explain would seem a natural progression to a mineralogist.

This issue is two-fold: First, as more information becomes available, we end up concentrating on smaller volumes of knowledge. We do not know that someone in another field has already worked on a problem in a different context. Second, in industry, one often cannot allow competitors to know what one is working on nor the level of understanding of a given problem.

Wallace D. Kleck, PhD
Tehachapi, CA

Dr. Langston responds:

Dr. Kleck’s observation on the primacy of the study of crystal structure and growth by mineralogists is well taken. Perhaps Pratt & Whitney’s Advanced Materials Research and Development Laboratory (AMRDL) team, led by Bud Shank, might have benefited from such geological world knowledge. (I do know that several of them had a geology professor for their undergraduate metallurgy course at Yale.)

I would guess that the time scales for crystal growth with geological mineral deposits (many years?) are different from single crystal turbine blades (hours).

Your mention of the necessity of industrial secrecy is right on, but with the single crystal blade project, competitor General Electric must have known something was going on there when their employee Frank VerSnyder quit and subsequently was hired by Pratt & Whitney Aircraft.