title: Compression-compression fatigue of selective electron beam melted cellular titanium (Ti-6Al-4V).
abstract: Regular 3D periodic porous Ti-6Al-4V structures intended to reduce the effects of stress shielding in load-bearing bone replacement implants (e.g., hip stems) were fabricated over a range of relative densities (0.17-0.40) and pore sizes (approximately 500-1500 μm) using selective electron beam melting (EBM). Compression-compression fatigue testing (15 Hz, R = 0.1) resulted in normalized fatigue strengths at 10(6) cycles ranging from 0.15 to 0.25, which is lower than the expected value of 0.4 for solid material of the same acicular α microstructure. The three possible reasons for this reduced fatigue lifetime are stress concentrations from closed porosity observed within struts, stress concentrations from observed strut surface features (sintered particles and texture lines), and microstructure (either acicular α or martensite) with less than optimal high-cycle fatigue resistance.
authors.affiliation: Materials Science and Engineering Department, University of Washington, 302 Roberts Hall, Seattle, Washington 98195-2120, USA. nhrabe@gmail.com
authors.forename: Nikolas W
authors.initials: NW
authors.lastname: Hrabe
authors.forename: Peter
authors.initials: P
authors.lastname: Heinl
authors.forename: Brian
authors.initials: B
authors.lastname: Flinn
authors.forename: Carolin
authors.initials: C
authors.lastname: Körner
authors.forename: Rajendra K
authors.initials: RK
authors.lastname: Bordia
mesh_terms: D000497:Alloys; D001672:Biocompatible Materials; D019245:Compressive Strength; D017076:Computer-Aided Design; D004583:Electrons; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning / Q000379:methods; D016062:Porosity; D011208:Powders; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D011208:Powders; C031462:titanium alloy (TiAl6V4); D014025:Titanium