Wear resistance enhancement of the titanium alloy Ti6AI4V via a novel co-incident microblasting process

A study was undertaken to investigate the potential of a novel surface modification process to
enhance Ti6Al4V wear resistance. The process consists of co-incident particle streams of
abrasive and dopant materials which impact a substrate to create a modified surface. Al2O3
was chosen as the abrasive and Teflon, SiC and B4C were investigated as dopants.
Al2O3-SiC and Al2O3-B4C modified Ti6Al4V both exhibited increased surface
hardness compared to the unmodified metal alloy. However, pin-on-disc tribometer
measurements indicated that such hardening modifications exhibited no appreciable benefits
in terms of wear resistance. On the other hand, Al2O3-Teflon modified Ti6Al4V demonstrated
significantly reduced coefficients of friction and reduced wear rates under the same test
conditions. Investigations suggest that although the Al2O3 abrasive is not incorporated into the
coating, its presence is essential in order to achieve a wear resistant surface. Combinations of
hard material (SiC or B4C) modifications with a further layer of Teflon resulted in further
enhancement of wear resistance as increased surface hardness was allied with similar low
coefficients of friction.
In conclusion, a number of the surface modifications conducted have a beneficial
affect on the wear resistance of Ti6Al4V. The process is also likely applicable to other
metal/metal alloys such as CoCr, NiTi and stainless steels. Furthermore, the chemical-free
nature and ambient temperature conditions concerned afford this process the potential to act
as an attractive alternative to some of the more problematic high temperature approaches
currently in use.