Structure and mechanical properties of explosive welded

Mg / Al bimetal

Institute of Materials Research SAV Košice,Slovak republic

Dušan Balga et al.| 2014 |

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Outline

1. our material

2. metallography

3. optical profilometry

4. SEM / EDX

5. microhardness

6. hard X-ray micro-diffraction experiment– phase analysis– computation of lattice parameters of Al and Mg

7. conclusion

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Mg / Al bimetal

• Cooperation and word of thanks:– prof. Ing. Eva Mazancová, CSc.– Ing. Dmytro OstroushkoVŠB-Technical University of Ostrava, Czech republic

manufacturer: EXPLOMET, PolandMg:- lightest among

metallic materials- density is about

2/3 of that of aluminium

- recycled without any degradation in physical properties

Al:- corrosion

resistance - high strength to

weight ratio- good formability

C o m b i n a t i o n o f M g a n d A l w o u l d b e p r o m i s i n g s t r u c t u r a l m a t e r i a l ( a e r o s p a c e , a u t o m o b i l e i n d u s t r y )

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Metallography

• average thickness of the interface 45 microns

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Optical profilometry

• the difference is approximately 8 microns (Al higher)

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Optical profilometry

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SEM/EDX

Element Weight% Atomic% O K 0.98 1.73Al K 90.04 94.28Cu K 8.98 3.99

Al

Element Weight% Atomic% O K 1.49 2.25Mg K 98.31 97.58Si K 0.20 0.17

weld, tilt of the specimen 70°

Mg

Mg

Al

SEM/EDX

Element

POINT:

Mg

[wt. %]

Al

[wt. %]

Si

[wt. %]

Fe

[wt. %]

Cu

[wt. %]

O

[wt.%]

1 6 27,3 0,4 34,1 32,2 -

2 3,7 81,7 - 1,6 10,5 2,5

3 85,4 11,7 0,2 - - 2,7

4 88,9 - 0,7 - 1,2 9,2

5 95,4 - - - - 4,6

Mg

Al

weld, tilt of the specimen 70°

Al

Al

weld, tilt of the specimen 0°

Micro - hardness

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• step: 120 microns• micro - hardness of the joined materials measured far

from their interface is similar for both materials• in the region of interface the hardness drops down by

40% to about 50 HV0.1

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Hard X-ray micro-diffraction experiment

beam size: 2,2 x 34 m

E= 99 keV

251 2D XRD patterns

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12

weld Al

Mg

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Phase analysis

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Al

15

Mg

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Conclusion– the results of metallographic and microchemical

analysis showed that a wavy Al / Mg explosive welded interface is molten in a very thin (45 m wide) region

– in the welded bond, there is substantial chemical inhomogeneity

– hardness in the middle of the Al / Mg interface region drops down by 40% from ~80HV0.1 to ~ 50 HV0.1 indicating some kind of thermal induced microstructure relaxation

– at the interface no intermetallics were observed– we proved an existence of solid solution with

gradually changed chemical composition from the centre of weld to the material

Acknowlegements• Ing. Karel Saksl, DrSc.

Institute of Materials Research SAV,

Slovak republic

• prof. Ing. Eva Mazancová, CSc.

• Ing. Dmytro OstroushkoVŠB – Technical University of Ostrava,

Czech republic

• the staffs at Beamline P07 – PETRA III, HASYLAB (DESY) – Germany for technical support during experiment

• Explomet Company• Slovak Grant Agency for

Science – Grant No. 2/0128/13

• Ministry of Education, Youth and Sports of Czech Republic– project No. L01203

"Regional Materials Science and Technology Centre – Feasibility program“

– project MK 9333413 No. 02613/2013/RRC “International research teams”

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THANKS FOR YOUR

ATTENTION

• Slovak Academy of Sciences• Institute of Material Research

• Kosice, Slovakia