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Improved contact load-bearing capacity of ultra-fine grained titanium : Multilayering and grading
journal contribution
posted on 2014-01-01, 00:00 authored by D K Yang, Jiangting Wang, Daniel FabijanicDaniel Fabijanic, J Z Lu, Peter HodgsonPeter HodgsonThe contact load-bearing response and surface damage resistance of multilayered hierarchical structured (MHSed) titanium were determined and compared to monolithic nanostructured titanium. The MHS structure was formed by combining cryorolling with a subsequent Surface Mechanical Attrition Treatment (SMAT) producing a surface structure consisted of an outer amorphous layer containing nanocrystals, an inner nanostructured layer and finally an ultra-fine grained core. The combination of a hard outer layer, a gradual transition layer and a compliant core results in reduced indentation depth, but a deeper and more diffuse sub-surface plastic deformation zone, compared to the monolithic nanostructured Ti. The redistribution of surface loading between the successive layers in the MHS Ti resulted in the suppression of cracking, whereas the monolithic nanograined (NG) Ti exhibited sub-surface cracks at the boundary of the plastic strain field. Finite element models with discrete layers and mechanically graded layersrepresenting the MHS system confirmed the absence of cracking and revealed a 38% decrease in shear stress in the sub-surface plastic strain field, compared to the monolithic NG Ti. Further, the mechanical gradation achieves a more gradual stress distribution which mitigates the interface failure and increases the interfacial toughness, thus providing strong resistance to loading damage. © 2014 Elsevier Ltd.
History
Journal
Materials and DesignVolume
58Pagination
217 - 225Publisher
Elsevier LtdLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0264-1275eISSN
1873-4197Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2014, ElsevierUsage metrics
Keywords
Contact load-bearingFinite element modelingGradingMultilayered hierarchical structureMultilayeringScience & TechnologyTechnologyMaterials Science, MultidisciplinaryMaterials SciencePLASTICALLY GRADED MATERIALSELASTIC-MODULUSDAMAGE RESISTANCERESIDUAL-STRESSINDENTATIONGRADIENTSDEFORMATIONSUBSTRATECOATINGSMECHANICSDUCTILEMechanical Engineering