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A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 1 6
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METALLURGY LANE
Metallurgy Lane, authored by ASM life member Charles R. Simcoe, is a continuing series dedicated to the early history of the U.S.
metals and materials industries along with key milestones and developments.
PIONEERS IN METALS RESEARCH—PART VI
THE INVENTION OF THE SINGLE CRYSTAL JET ENGINE BLADE UNDER FRANK
VERSNYDER AND A TEAM OF SCIENTISTS AT THE PRATT &WHITNEY DIVISION OF
UNITED TECHNOLOGIES IS CONSIDERED ONE OF THE 50 GREATEST ADVANCES IN
METALLURGICAL HISTORY.
T
he research program involving
single crystal jet engine blades be-
gan in the early 1960s at the Pratt
& Whitney Division of United Technolo-
gies Corp. It was spearheaded by Francis
Louis VerSnyder who had just joined the
company. During this era, Pratt & Whit-
ney was expanding its research efforts
into making major improvements in the
metal alloys used in the hottest part of
the jet engine. This initiative was a long-
range project with a goal of eliminating
failures that sometimes occurred at the
grain boundaries of cast turbine blades.
These blades were made of nickel base
alloys that could withstand the extreme
operating temperatures.
VerSnyder grew up in Watertown,
N.Y., as an only child in a single par-
ent household. His mother died at his
birth, and his father was old enough to
be his grandfather. In the 1940 census,
VerSnyder was listed as 14 years old
and his father as 56. He attended local
parochial schools through high school
and joined the army in 1943 at age 18.
He served in the 54th Armored Infantry
Division in Italy, France, and Germany.
He was wounded several times and re-
ceived the Purple Heart with Oak Leaf
Cluster and campaign ribbons with four
battle stars. He was discharged in fall
1945, still just 20 years old.
VerSnyder attended Notre Dame
University on the GI Bill, earning a B.S.
in Metallurgical Engineering in 1950. He
then joined the Small Aircraft Engine
Division of General Electric Co. in Lynn,
Mass. By 1955, he had transferred to the
Central Research Laboratories of GE in
Schenectady, N.Y., where he remained
until 1961 when he was recruited by
Maurice Shank from the Pratt & Whitney
Engine Division of United Technologies
Francis Louis VerSnyder.
Corp. At P&W, he supervised a newgroup
that had a 10-year goal of improving the
reliability of engine blades operating in
the hottest part of the engine.
GRAIN BOUNDARIES
IN CASTINGS
When molten metal is cast into a
ceramic mold, solidification begins at
the cold wall of the mold. The solid met-
al grows as crystals into the remaining
liquid until it fills the complete space of
the mold. Each of these growing crys-
tals—or grains—contacts other grains
that are growing at different orientations
in space. Where they meet, they form
boundaries that must adjust to these
different orientations. These boundaries
are weak regions in the alloy.
Cast turbine blades have many
grains that can be seen by chemically
etching the surface. Some areas of the
boundaries lay along the length of the
blade while others lay across it, called
transverse boundaries. In operation,
blades spin at very high revolutions
per minute so the major stress is along
the blade’s length. The boundaries that
cross the blades are the ones that are
weak during operation, and failure can
occur by separation at these boundaries.
DIRECTIONALLY SOLIDIFIED
ENGINE BLADES
The original goal of the pro-
gram was to grow grains in only one
Maurice “Bud” Shank.
VerSnyder received the National Medal of
Technology and Innovation in 1986.