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NATIONAL ACADEMY OF SCIENCES OF UKRAINE
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
The E.O. Paton Electric Welding Institute (PWI)3D Metalforming
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1. Title
2. Speaker
Ing. Sergei ILLARIONOVThe E.O. Paton Electric Welding Institute (PWI) of NAS of UkraineDepartment on Welding, Cutting and Treatment of Metals by Explosion 11 Bozhenko Str., Kiev, 03680, Ukraine Tel./fax: +380-44-205-25-53E-mail: [email protected]
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Explosive Cladding of Brittle Refractory MetalsS.Yu. Illarionov, L.D. Dobrushin, S.D. Ventsev, H.D. Groeneveld
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Re Nb Ta Mo W
3. Subject of our interest
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Considered as refractory metalsbecause of their melting point is more than 2200°C
Mo W
Subject of our interestThey are highly demanded by different high-tech industries as coatings
BUT THEY ARE RELATIVE BRITTLE
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During several decades explosion welders cladhigh-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
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5. State of the Art
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Friction stir weld in high-strength Al alloy 7010 was destroyed whenexplosively clad and just with hammer
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6. State of the art
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Successfully clad at 150°
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7. Brittle – Ductile Transition
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Some materials, especially metals withbody-centered cubic lattice, have relatively narrow brittle-ductile transition temperature range
The simplest explanation scheme ofbrittle-ductile transition effect
1 – Ultimate tensile strength2 – Yield strength
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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.
PuritySurface
roughnessDeformation
velocity
Stressstate
Grainsize
Thickness
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9. Plate thickness influence
0.3 mm thickness Mo clad to stainless steelat 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 thethicker metal is more difficult, especially in the central part of the plate. Secondly, the thicker plate, thehigher probability of the presence of rolling defects. These factors impede the movement of dislocations and, consequently, make the metal more brittle
1 mm thickness Mo clad to copper at ambient temperature
Cracks
Cracks
Copper
Molybdenum
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10. Successful realization
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
1 mm thickness molybdenum successfully clad to copper at 60°C
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11. Successful realization
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
1000 x 600 mm copper-molybdenum plate
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12. Plate thickness influence
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
0.5 mm thickness tungsten clad tocopper at ambient temperature
1 mm thickness tungsten clad tocopper at 400°C
0.5 mm thickness tungsten clad tocopper at 400°C
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13. Deformation velocity influence
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Increasing the deformation velocity of a cladding plate leads to moving the brittle-ductile transitiontemperature 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 muchfaster, so the difference between them decreases. In this case, materials becomes more brittle underexplosion loading and higher temperature is required to avoid cracks.
Dynamic YS – relative deformation velocitydependence for lowcarbon steel
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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
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15. Common methodology for finding critical brittle-ductile transition temperature
EXPLOSIVE CLADDING OF BRITTLE REFRACTORY METALS
Cracking occurs duringexplosive cladding atambient temperature
Toughness – temperaturedependence test proceduresat 20…400°C
* Making tests above 400°C is notreasonable
Explosive welding must be done at the temperature 50…100°C higher than it wasfound with toughness tests
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THANKS FOR YOUR ATTENTION!
