Product Code: ICAL08_M606

Laser Cladding of Ti-Nb Alloy on Mild Steel using Fiber Laser
Authors:
Amir Khajepour, University of Waterloo; Waterloo ON Canada
Vahid Fallah, University of Waterloo; Waterloo ON Canada
Stephen Corbin, University of Waterloo; Waterloo ON Canada
Presented at ICALEO 2008

Low elastic modulus, superior corrosion resistant, significantly reduced field of ignition and high biocompatibility of Ti-45Nb have attracted a wide interest for various applications including medical implants, highly corrosive and oxygenated environments such as autoclaves, pressure vessels and heat exchangers. Furthermore, clad metal constructions offer a considerable cost reduction for equipment of this type in comparison to solid titanium alloy [1,2].
This paper reports the laser cladding of Ti-Nb on mild steel using pre-placed bed technique. A premixed powder of 55wt% Ti and 45wt% Nb is used and a number of tracks were successfully laid at various processing parameters. The results indicate that defect free and well bonded single clad layers with an excellent hardness (up to 1000 HV0.05) can be achieved with a relatively high dilution from the substrate. The processing parameters are set to ensure extremely short interaction times (less than ~0.03 s), while applying a high laser power. Characterization of clad materials using microhardness, EDS, SEM and XRD has shown that applying slightly longer interaction times results in the formation of a number of brittle intermetallics between Fe and either Ti or Nb, rather than solid solutions in Ti-Nb system. The microhardness values and the types of intermetallics (formed at longer interaction times) found to be dependent on the beam interaction time.