Wire electric discharge machining induced titanium hydride in Ti–46Al–2Cr alloy

Wire electric discharge machining (Wire-EDM) induced a new phase in Ti–46Al–2Cr (in at.%) intermetallic alloy has been identified by using X-ray diffraction technique. The new phase is found to be neither TiO2 nor Al2O3, but well consistent with fcc structure titanium hydride with the lattice parameter of 4.49–4.50 Å. The new phase exists in the wire-EDM cut alloy surface layer limiting to about 70 μm thick, much deeper than the wire-EDM induced recast layer thickness of 2–3 μm. One processing, vacuum annealing at 400–600 °C, has been proposed to remove this hydride induced by wire-EDM. In addition, The wire-EDM induced microcracks extensively happen on the EDM-cut surface and penetrate into matrix up to 10–30 μm.