title: The effect of microstructure on fatigue performance of Ti-6Al-4V alloy after EDM surface treatment for application in orthopaedics.
abstract: Three different microstructures--equiaxed, bi-modal and coarse lamellar--are prepared from Ti-6Al-4V alloy. Electric discharge machining (EDM) with a high peak current (29 A) is performed in order to impose surface roughness and modify the chemical composition of the surface. Detailed scanning electron microscopy (SEM) investigation revealed a martensitic surface layer and subsurface heat affected zone (HAZ). EDX measurements showed carbon enriched remnants of the EDM process on the material surface. Rotating bending fatigue tests are undertaken for EDM processed samples for all three microstructures and also for electropolished-benchmark-samples. The fatigue performance is found to be rather poor and not particularly dependent on microstructure. The bi-modal microstructure shows a slightly superior high cycle fatigue performance. This performance can be further improved by a suitable heat treatment to an endurance limit of 200 MPa.
authors.affiliation: Charles University, Department of Physics of Materials, Prague, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Stráský
authors.forename: Miloš
authors.initials: M
authors.lastname: Janeček
authors.forename: Petr
authors.initials: P
authors.lastname: Harcuba
authors.forename: Michal
authors.initials: M
authors.lastname: Bukovina
authors.forename: Lothar
authors.initials: L
authors.lastname: Wagner
mesh_terms: D000497:Alloys; D004560:Electricity; D006358:Hot Temperature; D008422:Materials Testing; D055595:Mechanical Phenomena; D008855:Microscopy, Electron, Scanning; D009985:Orthopedics / Q000379:methods*; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; C031462:titanium alloy (TiAl6V4); D014025:Titanium