Tuskegee University:

Collaborative Research with the Boeing Company

Legand Burge, Dean Heshmat Aglan, Associate Dean

College of Engineering

David Burdick The Boeing Company

Presented at BEYA 2015, Washington DC

The College of Engineering Enabling Education and Leadership; Exploration and Discovery; Engagement and Service; Technology and Application by Legand L. Burge, Jr., Dean

TM

Tuskegee University Overview Independent and state-related institution of higher

education The academic programs are organized into five

colleges and two schools The curricula for these colleges and schools currently

offer over 50 degrees including 39 Bachelor's, 13 Master's, 3 Doctor's of Philosophy: Materials Science and Engineering, Integrative Bio-Sciences, Interdisciplinary Pathobiology and the Doctor of Veterinary Medicine. Tuskegee enrolls more than 3,000 students and

employs approximately 900 faculty and support personnel. Physical facilities include more than 5,000 acres of

forestry and a campus on which sits more than 100 major buildings and structures.

College of Engineering (CE)

CE

AEROSPACE SCIENCE

ENGINEERING

MECHANICAL ENGINEERING

ELECTRICAL ENGINEERING

CHEMICAL ENGINEERING

WITH ENVIRONMENTAL

OPTION

MATERIALS SCIENCE &

ENGINEERING

Tuskegee University partner with prime Jacobs Engineering on ESSSA – Prime with NASA

NASA Mentor-Protégé Program Jacobs Engineering (ETSA) Current Kr for Products, Services, Consultancy – Dynetics;

Aerojet; Teledyne Brown; Boeing; Lockheed Martin; Raytheon Proposals with URS, L-3 Comm, SAIC $12.5M – Government Grants/Contracts (NSF, DoD, NSA,

CIA, DoEd, DoEnergy, USDA, FAA, DOT(FRA), NRC, Pending Proposals - $8M Career Fair, Fall 2015: Internships/Cooperative Ed Talent Acquisition – Fortune 500 Companies Benchmark Industries – Procter & Gamble; Ford Motor; 3M;

Boeing Co., Nucor Steel Co., Chevron; ExxonMobil; Boeing; Lockheed Martin; John Deere; Jacobs; Kellogg; Southern Company; Microsoft; Nucor

Overview - College of Engineering – Past Performance

Utilize current infrastructure for insert Veterans into undergraduate and graduate courses

Tuskegee University current partnership with consortium institution easy to add to ongoing courses and internship experiences particularly with prime from NASA, e.g., Jacobs Engineering in Huntsville, AL, Steins, MS, Orlando, FL, etc.

Undergrad programs provide ease to move into STEM areas Graduate programs focus on Systems Engineering (Navy) Utilize HBCU Engineering Deans (14) to utilize nation-wide

approach for Veterans, particularly for southeastern states Utilize Fortune 500 collaborations Utilize nation-wide Career Fair, online and for

Internships/Cooperative Ed for Vets GI Bill funding easy for Online/On-campus courses/programs Talent Acquisition – Fortune 500 Companies

Proposal Overview - College of Engineering

Selective Research Capabilities Nucor Education and Research Center (NERC) : Focuses on industry based research in the latest trends in steel technologies including dual phase microstructure, HSLAS, weathering and corrosion resistance and high impact resistant steels, etc.

Nanomaterials Lab: Focuses on fabrication, chemical, thermal , and mechanical characterizations of high performance materials that include thin films for the next generation solar concentrators, nanostructured conformable coatings, proton and anion conducting membranes, etc.

Building Materials Lab: Development; testing and evaluation of energy efficient building materials including Composite Structural Insulate Panels (CSIPs), thermally resistive cement binders, nanostructured cementitious surface compounds and remediation of oil polluted building components, etc.

NUCOR –Education and Research Center (NERC)

• The Center is comprised of three main components: • Educational • Research • Outreach

• The NERC pursues a balance between these components to provide engineering graduates with basic and applied knowledge of steels and their related technologies.

NERC Research

• Microstructure- properties relationship of structure steels • Processing- properties relationships of structure steels • Analysis of surface defects in hot and cold rolled steels • Accelerated corrosion studies on enameled and galvanized

steels • Microstructure – properties relationships of low carbon steels • Improvement of wear, strength and corrosion resistance of

carbon steels using nanocoatings.

Microstructural Analysis of Bainitic and Pearlitic Rail steels

0200400600800

1000120014001600

0 2 4 6 8 10 12 14

Stre

ss

MPa

Strain %

Pearlitic steel

Bainitic steel

Microstructure of rail steel dictates its overloading behavior. pearlitic

bainitic

Microstructural Gradient of Old and New Railheads

Fine grains due to head hardening. More ductile features

Elongated grains due to service shear and compressive loading.

Brittle-like features

New railhead Old railhead

Detection and Assessment of Low Cycle Fatigue Damage

Fatigue Crack Propagation Kinetics of Bainitic and Pearlitic Rail Steels

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

0 10 20 30 40 50 60 70Energy Release rate, J* (kJ/m2)

Cra

ck G

row

th r

ate,

da/

dN

(m/c

ycle

)

Bainitic Pearlitic

Fatigue crack propagation kinetics correlation with fracture surface morphology. (fast crack region)

bainitic

pearlitic

Rail Steel Repairs

Rail Steel after Welding

Slot weld Continuous weld

Hypervelocity Impact Analysis of Aerospace Materials

Phenolic Resin Aluminum Alloy Silicon Carbide

Plasma Drag Hypervelocity Particle Accelerator

Fracture and Fatigue Studies of Vanadium Alloys

Processing Orientation Fracture Toughness Relationship of Vanadium Alloys

Nanostructured Polymeric and Cementitious Materials

Well dispersed Acid treated MWCNTs

Dispersion of Nanoparticles

Mechanical Performance of Nanostructured MWCNT Tetrafunctional Epoxy Systems

020406080

100120140160180200

0 0.2 0.4 0.6 0.8 1 1.2Deflection, mm

Flex

ural

Stre

ss, M

Pa

nano

neat

MWCNT dispersed in epoxy matrix A considerable enhancement in the flexural strength has been achieved with MWCNT

reinforcement.

Thermal Conductivity of Aligned MWCNT

Number of

Stack Layers

Thermal

Resistance

( m2K/W)

Overall Stack

Assembly

Thickness (mm)

MWCNT/

Epoxy

Thickness (mm)

Thermal

Conductivity

(W/mK)

3 6.79E-3 8.59 2 178

2 6.29E-3 8.0 1.4 178

1 5.96E-3 7.1 0.4 178

.

Summary of thermal resistances and corresponding thicknesses of stacks

Fabrication of Thin Films

Neat Polyimide Film 0.5%MWCNT Polyimide Film

Fabrication

Woven Carbon/Phenolic Composites

Pulse Laser Degradation of Nanostructured Composites

0 5

10 15 20 25 30 35 40 45

0 0.5 1 1.5 2 2.5

Stre

ss, M

Pa

Strain, %

Neat Epoxy - 2 min 0.15% MWCNT/Epoxy - 2 min 2% NC/Epoxy - 2 min

Top view of the laser damaged area of the (a) neat epoxy, (b) 2% nanosilicate/epoxy and (c) 0.15% MWCNT/epoxy.

a b c

UV Aging of Polymers

0

5

10

15

20

25

30

35

40

0 0.5 1 1.5 2

Stre

ss, M

Pa

Strain, %

1 month 2 months 3 months 4 months

Neat Epoxy

0

1

2

3

4

5

6

7

0 10 20 30 40 50 60 70 80 90 100

Strain(%)

Str

ess

(MP

a)

Before aging1 Month UV2 Months UV3 Months UV4 Months UV5 Months UV

Before Aging 1 Month

2 Months

3 Months

4 Months5 Months

Neat Polyurethane

0

5000

10000

15000

20000

25000

30000

35000

-20000 0 20000 40000 60000 80000 100000 120000 140000

Imag

inar

y a

xis,

-Z (Ω

)

real axis, Z (Ω)

18%MPI 21% MPI 25% MPI 30% MPI

1.5 MHz

10 Hz

10 Hz 10 Hz

Proton Conductivity

Nanoparticle Proton Conductivity, (S/cm)

Membrane Nanostructured

Membrane Increase, %

Activated Silica 1.28×10-5 1.44×10-5 12.5

Fumed Silica 5.14×10-5 1.44×10-4 180

Liquid Silica 2.6×10-3 1.4×10-2 400

Sand-Jet Edge Erosion of Coated Graphite Epoxy Composites

Uncoated Coated

Typical values of mass loading vary from 0.0001 g/cm2 (extremely light) to 1.0 g/cm2 (extremely heavy).

Nanoreinforced Coatings

Before immersion

Neat VYHH 20 days

immersion

Nano VYHH 20 days

immersion

• Corrosion and blistering started on the neat VYHH coated sample (middle) • Nanocoatings have shown no corrosion for the same immersion period

Neat VYHH

Nano VYHH

Effect of Nanosilicate Loading on the Mechanical performance of Cementitious Compounds

0

2

4

6

8

0 2 4 6 8 10

Indi

rect

Ten

sile

Stre

ngth

, MP

a

NS Replacement Ratio, %

Unactivated nanosilicate Activated nano silicate

AFM morphology of un-activated material AFM morphology of activated material

Expandable Thermoplastic Microspheres (ETM) Study

Hollow microspheres filled with hydrocarbons gaseous Expand upon heating (150~200 C) Loading in cement ranges was up to 1%wt.

Un-expanded

Expanded

Cement binder

Cement binder with 1% wt.ETM

Lab and Field Testing of Energy-Efficient Flood-Damage-

Resistant Residential Envelope Systems

Flooding for 3 days

Flooding for 21 days

Mold growth upon re-entry after flooding

Samples taken for mold identifications

A research effort to understand the growth mechanism of Tin Whiskers and methods of risk

mitigation

By

David Burdick, The Boeing Co. Heshmat Aglan, Tuskegee University

The Banned Substance

The European Union’s RoHS (Reduction of Hazardous Substances) legislation banned the use of four hazardous materials one of these materials was Lead. Lead is used in solder alloys

The Change

Lead is also used as a plating material for high performance electronic components

Component terminations are plated with Tin/Lead solder

The Problem

The replacement plating material is Tin and to our disadvantage Tin grows whiskers.

What are Tin Whiskers Tin Whiskers are electrically

conductive single crystalline tin structures that grow from pure tin-plated surfaces

They can and have caused short circuits in electronic circuits

They can break from the surface and interfere with the operation of mechanical or optical assemblies

They are a threat to the aerospace and defense industry

Tin whiskers (Courtesy of NASA)

What are Tin Whiskers

Tin Whiskers Up Close (Courtesy of DUART Productions)

Tin whisker growing from tin surfaces near electrical components

Tin whisker growing from the surface of tin connector guides.

(Acquired from nepp.nasa.gov)

How do they Cause Shorts

(Acquired from nepp.nasa.gov)

Shorts Cause Equipment Failures On-Orbit commercial (non-NASA) Satellite failures:

GALAXY VII (PanAmSat) Both primary and redundant SCP failed SOLIDARIDAD 1 (SatMex) Both primary and redundant SCP failed GALAXY IIIR (PanAmSat) Both primary and redundant SCP failed

Medical Equipment Failures:

Heart Pacemaker Recall Apnea Monitor Failures

Industrial Power Failures Dresden Nuclear Reactor - Tripped Channel B Duane Arnold Nuclear Reactor - Reactor Scram Duane Arnold Nuclear Reactor - Reactor Scram/Controlled Shutdown Dresden Nuclear Reactor - Reactor Scram Dominion Millstone - Reactor Trip

Military System Failures

Patriot Missile Phoenix Missile F-15 Radar

Tuskegee’s Research Project

Many scientists agree that compressive stress in the tin film is the fundamental driving force behind tin whisker growth.

Other factors proposed are oxidation, re-crystallization,

thermal mismatch between metallic surfaces, corrosion, impurities, inter-metallic compound growth and migration.

The students at Tuskegee University are attempting to determine the root cause of Tin Whisker growth and to find a way to mitigate the risks they cause to electronic circuits.

Observation of Tin Whisker Growth under Hygro-Thermal Exposure and 5% NaCl Water Immersion

funded by Boeing Co.

Whiskers protrusion seen at magnification 5KX

Thermotron Test Chamber (a) (b)

Coupons arrangement – (a) Thermotron and (b) Corrosion chambers

(a) (b)

The First Step in the Process

Tin plated brass coupons immersed in 5% NaCl solution.

Tuskegee is Growing Whiskers

Coupons Used in the Research at Tuskegee

Coupons removed from the NaCl Solution show signs of corrosion that may induce stresses. The next step is to check for

Tin Whiskers

(c)

(d) (e)

How do we find a Whisker

Optical Microscope (Olympus G5000) Scanning Electron Microscope (Hitachi S3400 N)

Optical Microscope Scanning Electron Microscope

Forensic Science

Why do we need microscopes?

Image provided by NASA

How do we know we have found one? After optical observations of something that looks like a

protrusion growing out of the surface, we confirmed our suspicion by elemental analysis using X-ray diffraction (XRD)

In this test tin whisker growth was evident by the elemental tin peak (100% tin shown)

SEM Micrographs showing (a) whisker growth and (b) XRD analysis showing 100% tin peak

Whiskers Growing at Tuskegee Whiskers were found Growing from a Sample coupon

(a) (b) Figure 23: SEM micrograph showing long and bent whisker from scratched flat coupon after 5700 hour exposure to corrosive environment (aqueous NaCl); magnifications are 5000X (a) and 3000X (b)

(a) (b) Figure 24: SEM micrograph showing conjoined whiskers from scratched flat coupon after 7000 hours of exposure to corrosive environment (aqueous NaCl); magnification is 4000X.

Tin Whisker Growth - Factors

Intermetallic

Tin

Copper Substrate Courtesy of: A History of Tin Whisker Theory George T. Galyon IBM eSG Group

Tin Whisker Growth - Factors

Whisker Nodule

Intermetallic Cu6Sn5 Tin (Sn)

Cu194

Courtesy of: A History of Tin Whisker Theory George T. Galyon IBM eSG Group

Next Steps

Sectioning at the root

Whisker root analysis

Study the migration of binary compounds

Follow the trail