1. The E.O. Paton Electric Welding Institute (PWI) 3D Metalforming
NATIONAL ACADEMY OF SCIENCES OF UKRAINE
The E.O. Paton Electric Welding Institute (PWI)
3D Metalforming
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS

2. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
1. Title
2. Speaker
Ing. Sergei ILLARIONOV
The E.O. Paton Electric Welding Institute (PWI) of NAS of Ukraine
Department on Welding, Cutting and Treatment of Metals by Explosion
11 Bozhenko Str., Kiev, 03680, Ukraine
Tel./fax:
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Explosive Cladding of Brittle Refractory Metals
S.Yu. Illarionov, L.D. Dobrushin, S.D. Ventsev, H.D. Groeneveld

3. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Re Nb Ta Mo W
3. Subject of our interest
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Considered as refractory metals
because of their melting point is more than 2200°C
Mo W
Subject of our interest
They are highly demanded by different high-tech industries as coatings
BUT THEY ARE RELATIVE BRITTLE

4. Low temperature heating prevents crack forming in the interface
During several decades
explosion welders clad
high-strength and brittle
materials that tend to
crack when explosion
loading is applied
4. State of the art
EXPLOSIVE CLADDING OF THIN METAL FOILS
Low temperature heating prevents
crack forming in the interface

5. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
5. State of the Art
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Friction stir weld in high-strength Al alloy 7010 was destroyed when
explosively clad and just with hammer

6. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
6. State of the art
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Successfully clad at 150°

7. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
7. Brittle – Ductile Transition
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Some materials, especially metals with
body-centered cubic lattice, have relatively narrow brittle-ductile transition temperature range
The simplest explanation scheme of
brittle-ductile transition effect
1 – Ultimate tensile strength
2 – Yield strength

8. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
8. Factors influencing on the brittle-ductile transition temperature
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
The brittle-ductile transition temperature is not a constant for certain metal or alloy.
It depends on many factors.
Stress
state
Purity
Surface
roughness
Thickness
Grain
size
Deformation
velocity

9. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
9. Plate thickness influence
0.3 mm thickness Mo clad to stainless steel
at ambient temperature
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Increasing of the thickness of a cladding plate leads to moving the brittle-ductile transition temperature to the higher values. This can be explained, firstly, by the fact that passage of plastic deformation in the
thicker metal is more difficult, especially in the central part of the plate. Secondly, the thicker plate, the
higher probability of the presence of rolling defects. These factors impede the movement of dislocations and, consequently, make the metal more brittle
Molybdenum
Cracks
Cracks
Copper
1 mm thickness Mo clad to copper at ambient
temperature

10. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
10. Successful realization
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
1 mm thickness molybdenum successfully clad to copper at 60°C

11. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
11. Successful realization
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
1000 x 600 mm copper-molybdenum plate

12. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
12. Plate thickness influence
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
0.5 mm thickness tungsten clad to
copper at ambient temperature
1 mm thickness tungsten clad to
copper at 400°C
0.5 mm thickness tungsten clad to
copper at 400°C

13. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
13. Deformation velocity influence
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Increasing the deformation velocity of a cladding plate leads to moving the brittle-ductile transition
temperature to the higher values. The simplified explanation is that increasing deformation velocity leads to increasing dynamic tensile strength and dynamic yield strength. However, the last one grows much
faster, so the difference between them decreases. In this case, materials becomes more brittle under
explosion loading and higher temperature is required to avoid cracks.
Dynamic YS – relative
deformation velocity
dependence for low
carbon steel

14. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
14. Detonation velocity influence
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
0.5 mm thickness tungsten clad to copper at 400°C
when D = 4000 m/s
0.5 mm thickness tungsten clad to copper at 400°C
when D = 2000 m/s

15. EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
15. Common methodology for finding
critical brittle-ductile transition temperature
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Cracking occurs during
explosive cladding at
ambient temperature
Toughness – temperature
dependence test procedures
at 20…400°C
* Making tests above 400°C is not
reasonable
Explosive welding must be
done at the temperature
50…100°C higher than it was
found with toughness tests

16. THANKS FOR YOUR ATTENTION!