DTIC ADA359889: Laser Induced Reaction for Prebond Surface Preparation of Aluminum Alloys; Stage 1

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LSSER INDUCED RESCTION FOR FHEBOND SURFACE
PREPJR1TI0N OF ALUHINUH 3LL0YS

Stage X Report (5-6/93)

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 27 June 3. REPORT TYPE AND DATES COVERED May-June 1993

1993

4. TITLE AND SUBTITLE Laser Induced Reaction for Prebond Surface
Preparation of Aluminum Alloys. Stage 1.

5. FUNDING NUMBERS F61708-93-
C005

6. AUTHOR(S) Rotel, M.; Zahavi, J. ; Buchman, A.; Dodiuk, H.

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

8. PERFORMING ORGANIZATION
REPORT NUMBER

Israel Institute of Metals
Technion Research and
Development Foundation Ltd.
Haifa, Israel

Materials and Processes Dept.
Rafael

Haifa, Israel

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)

EOARD

PSC802 Box 14
FPO 09499-0200

10. SPONSORING / MONITORING
AGENCY REPORT NUMBER

SPC 93-4019-1

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I 9 990 2160 6 3

NSN 7540-01-280-5500

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39-18 298-102

LASER INDUCED REACTION FOR PREBOND SURFACE
PREPARATION OF ALUMINUM ALLOYS

Stage I Report (5-6/93)
Contract No. F61708-93-C005

by

M. Rotel, J. Zahavi

Israel Institute of Metals, Technion, Haifa, Israel

A. Buchman, H. Dodiuk
Materials and Processes Department,
RAFAEL, Haifa, Israel

Haifa, June 27, 1993

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INTRODUCTION

The potential of UV lasers for prebonding treatment of Al-2024
alloy was proved in a previous investigation [1] with a
modified epoxy adhesive.

Surface treatment of A1 by excimer laser results in oxidation
and morphological changes of the surface promoting high shear
adhesion strength at optimal laser conditions. The objective
of this research is to establish the effect of excimer ArF UV
laser on the A1 alloy surface microstructure and chemical
activity and its correlation with the macro behaviour of shear
and peel strength and failure locus of adhesively bonded
joints using structural adhesives for structural and repair
applications.

The first stage of this research (OGGI of the contract) is
summarized in this report. This stage includes the preparation
of all A1 specimens with required configurations for the
various tests.

EXPERIMENTAL

Adhesives and Primer

3 kinds of structural adhesives for various service
temperatures and their primer were ordered. The details of the
adhesives and the primer are given in Table 1.

Table 1: The structural adhesives and the primer

COMMERCIAL

NAME

(CYANAMID)

CURING

CONDITIONS

APPLICATION

FORM

SERVICE

TEMPERATURE

RANGE

FM73

1 Hr. 120°C
40psi

FILM,0.38mm

POLYESTER CARRIER

•

-55°C to +120°C

FM3002K

1.5Hr. 120°C
40psi

FILM,0.3mm
POLYESTER CARRIER

-55°C to +175°C

FM350NA

lHr. 177°C
30psi

FILM

GLASS CARRIER

-65°C to +177°C

BR127

l/2Hr. R.T
l/2Hr. 121 C

MIXING,BRUSHING

-55°C to +177°C

All adhesives and the primer will pass quality control tests
including epoxy content, solid content, volatiles and percent
of fluency, before application.

Adherends Preparation

Four kinds of A1 2024 adherends were prepared:

1- Single lap shear adherends (see Fig. 1) according to ASTM
D-1QQ2-72

25 X 100X 1.6 mm (2 for each sample).

Peel adherends according to ASTM D-3167 (see Fig. 2).

25 X 250 X 1.6 mm (rigid).

25 X 250 X 0,5 mm (flexible).

(One of each for each sample).

2 -

3-

Tensile adherends according to ASTM C-297
(Flat wise, FW)

37 X 37 X 37 mm with a central penetrating, hole
(described in Fig. 3)

(2 for each sample).

4- Wedge adherends

According to ASTM D-3762

25 X 250 X 1.6 mm

(2 for each sample + a wedge).

The sample is described in Fig. 4.

I 6 mm
{0.064")

GLUE LINE

c

1^2

225.4.*

mm

AREA

IN¬

TEST

GRIPS

u*-

- L*_

63.5 mm- -63.5 mm —
- 1271 L mm-*1

-177.8 t L mm-

i

- 25.4a

mm

SHEAR

"AREA

AREA

V !N

TEST

GRIPS

Fig. 1: SLS adherends.

ALUMINUM OR STAINLESS STEEL WEDGE

j—-1 Q "±0.03 —.
1

]

* I

1

0" ±0.03

I

iJ

v

l - 1

-0.125" NOMINAL

-0.25" ±0.03

Fig. 4: Wedge test adherend.

Amount and Kinds of Samples

Two kinds of references will be used in all experiments for
comparison with laser treated specimens. A non-treated A1
sample. An unsealed chromic acid anodized A1 sample
(MIL-A-8625C).

SLS adherends will be tested at various laser parameters + 2
references in order to establish the optimal laser conditions.

Peel, tensile and wedge tests will be produced at optimal
laser conditions only + 2 references.

The total amount of sample sets prepared are summarized in
Table 2•

Anodization treatment for the reference adherends will be
performed as close as possible to the adhesion stage.

Table 2: Number of sets needed for the various tests

Adherends

Adhesive

FM 73

Peel Tensile Wedge

( 1 ) ( 1 ) ( 2 )

FM300 2K

Laser irradiated

Untreated

Anodized

Laser irradiated
Untreated

Anodized

FM350NA

Laser irradiated

Untreated

Anodized

(1) Each set = 5 samples

(2) Each set = 3 samples

The total amount of samples prepared are:

SLS (Shear)
FW (tensile)
PEEL (90°)
Wedge

75 samples
45 samples
45 samples
27 samples.

SUMMARY

All adherends for the various tests were prepared. Adhesives
and primer were ordered and will be QI tested when received.
Task No. GG01 was completed.

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