February/March_AMP

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 | F E B R U A R Y Y / M A R C H 2 0 1 7

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A CENTURY OF PROGRESS AT THE

MATERIALS AND MANUFACTURING

DIRECTORATE

Throughout its 100-year history, the Materials and Manufacturing Directorate

(ML) has conducted groundbreaking critical research programs responsible for a

multitude of technological advances.

Fig. 1 —

Early polymer research within the

Materials Laboratory, 1948.

he Materials and Manufacturing

Directorate was created in 1917 as

theMaterials LaboratoryatMcCook

Field in Dayton, Ohio, to provide lighter,

stronger, and more reliable materials for

the growing aerospace community. Not

surprisingly, initial research focused on

improving the flexible wood products

used in airplane structures. Various met-

al alloys were also used for engine com-

ponents, propellers, and landing gear,

leading to research efforts in metallurgy,

casting, and materials processing. For

example, this early research enabled de-

velopment of a carburized armor plate to

protect against armor-piercing ammuni-

tion. The material resisted bullets travel-

ing 2200 feet per second—a tremendous

improvement over conventional mate-

rials of the time. This work provided the

foundation for 41xx class steel alloys. The

laboratory moved to Wright Field in 1927

and continued groundbreaking research

activities, including development of a

rotating beam fatigue machine, which

enabled uniform loading of material test

specimens. The new design revolution-

ized testing procedures and set the in-

ternational standard for characterizing

fatigue properties.

WARTIME ADVANCEMENTS

The start of WorldWar II necessitat-

ed an increased emphasis on materials

Jaimie S. Tiley, FASM,* and Amy Whitney-Rawls

Air Force Research Laboratory, Wright-Patterson AFB, Ohio

*Member of ASM International

development and improved processing

capabilities. ML provided manufactur-

ing assistance to weapons producers

and engineering support to improve

aircraft capabilities. In addition, re-

quirements to accelerate weapon sys-

tems production and find substitutes

for materials that were in short supply

created new research directions. For

example, innovative materials such as

butyl rubber and nylon were developed

to replace the natural silks used in para-

chutes. Radar technologies and light-

weight structural components were

also developed to meet new military

demands. Service issues were targeted

as well, including assessments of the

B-17 bombers, which were discovered

to contain cracks in the wing spars. ML

developed steel reinforcement plates

that were applied to keep the fleet fly-

ing and successfully avoid wing failures.

In 1948, ML launched a flu-

orocarbon

research

group

spon-

sored by the Petroleum Product

Unit, which grew to become the

in-house polymer group (Fig. 1).

Research addressed critical needs for

advanced polymers, including require-

ments for stable polyester materials

in transparent radomes used in air-

borne radar applications and develop-

ment of high stiffness glass fibers. The

fibers were used to create lightweight

composite materials to structurally

compete with aluminum. Successful

development of “S glass” was transi-

tioned and used in filament-wound

rocket motor cases for the third stage of

the Minuteman II intercontinental bal-

listic missile (ICBM).

SPACE AGE RESEARCH

In the early 1960s, advanced efforts

in developing boron filaments, compos-

ites, and dispersion hardening alloys

were initiated. In addition, the Rare

Earth Permanent Magnet Materials Ini-

tiative was established to research the

high magnetic properties of rare-earth

transition element intermetallic com-

pounds. This research led to develop-

ment of samarium cobalt magnetic