PHYSICAL
FEATURES Titanium
is a pure element: we find it in nature as oxides and its very common on
earths crust: its the 9th element for abundance and the 3th metal
to use in mechanical constructions, after Aluminium and Iron. Its included
in the periodic table of the elements of the IV group and IV period. The atomic
number is 22 and its trend is first of all metallic, even if its a transiction
element.
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| Copper
Electrodes (Cu) are the priority for the heat squandering created by the
electric pulse lasting 250 300 milliseconds.
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SINTERIZATION compaction
of Titanium superior prismes undergoing a great pression united to a temperature
increase equal to 70% of that fusion. |
SYNCRYSTALLIZATION
Deep crossover of prismatic crystals through the union of atoms in the
construction of the crystal lattice |
In
the whole welding cycle we can distinguish 3 phase: 1 - Approaching
phase: during which there is only the application of pressure without current 2
- Welding phase: where the pressure and current are simultaneous up to the core
fusion 3 - Cooling phase: where there's no current wile the pressure
is maintained |
COOLING
PHASE Its also important because in this phase metal crystallizes
and you need to keep it under pressure |
The
passing current will develope an heat as more intense as high is the present resistance, LAW
of JOULE:
 Q=
heat quantity expressed in calorie degrees (Cal) J= mechanical equivalent
of the big calorie expressed Joule/Cal (1Cal=4,18x10³ J) I= current
intensity in ampere R= electric resistance in Ohm t= time
in seconds
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Pulse
without Argon
 | Images
at different enlargements of the welded joint with an only pulse without Argon
a). b) Image by back-scattering system. c), d) e f) images by signal of
secondary electrodes (after etching) |
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Pulse
without Argon
 | Image
SEM of the welded joint by an only pulse without argon and analysis EDS of the
marked areas: a) welding, b) wire |
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Pulse
with Argon
 | Different
enlargements of the welded joint by an only pulse with Argon a). b) Image
by back-scattering method. c), d) e f) images by signal of secondary electrodes
(after etching) |
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Pulse
with Argon
 | Image
SEM of the welded joint by an only pulse with argon and analysis EDS of the marked
areas: a) welding, b) wire |
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