A method of welding titanium, and titanium based alloys, to ferrous metals is described. Welding of titanium, and titanium based alloys, is plagued with poor quality and highly brittle welds, substantially due to formation of Ti—Fe intermetallics in the weld pool. The instant invention provides supplementary filler material to alter the proportions of various elements in the weld pool. Certain fillers, such as nickel or iron, added to the weld pool enable high quality welds to be fabricated utilizing a wide variety of fusion welding techniques, including laser welding, between titanium, or titanium based alloys, and ferrous metals, including but not limited to the welding of nickel-titanium and stainless steel. Filler material may be supplied in various forms, including foil, wire, powders, preformed gaskets, and numerous others. Optionally, the titanium or titanium based alloy may be stress relieved to achieve full recovery of the shape memory strain prior to welding.