Titanium is used in sea water applications because of its
good corrosion and
properties. In aggressive conditions, however, environment
hydrogen embrittlement of titanium may be a problem.
Hydrogen uptake is possible
especially when titanium is connected with steel parts
which are cathodically
order to prevent corrosion. The possible cracks in
titanium parts may absorb
produced by cathodic reaction.
The aim of this study has been to examine whether
titanium shows accelerated
crack growth caused by hydrogen embrittlement under
cathodic polarisation. The
materials were unalloyed titanium (Grade 2) and Ti-6A1-4V
(Grade 5). The crack
growth rate tests were performed in flowing ASTM sea
water at room temperature
a servo hydraulic universal testing machine equipped with
an environment cell.
applied potentials were -800 mV ... -1500 mV vs.
saturated calomel electrode
For comparison, crack growth rate tests in air for both
materials were also performed.
Cathodic polarisation in sea water did not accelerate the
crack growth in
2 type titanium compared with the crack growth rate in
air. For titanium Grade
applied cathodic potentials slightly accelerated the
crack growth in the
potential range of
-800 ... -1050 mV(SCE). However, at the lowest applied
potentials, -1200 and
mV(SCE), the crack growth rates decreased again to even
lower rates than was
for the same material in air.
No effect of hydrogen on the fracture surface morphology
of the fatigued
observed in the scanning electron microscopy examination.
|Place of Publication||Espoo|
|Publisher||VTT Technical Research Centre of Finland|
|Number of pages||40|
|Publication status||Published - 1992|
|MoE publication type||Not Eligible|
- titanium alloys
- corrosion fatigue
- cracking (fracturing)
- crack propagation
- hydrogen embrittlement
- cathodic polarization
- sea water