title: Microstructure, texture evolution, mechanical properties and corrosion behavior of ECAP processed ZK60 magnesium alloy for biodegradable applications.
abstract: Ultra-fine grained ZK60 Mg alloy was obtained by multi-pass equal-channel angular pressing at different temperatures of 250°C, 200°C and 150°C. Microstructural observations showed a significant grain refinement after ECAP, leading to an equiaxed and ultrafine grain (UFG) structure with average size of 600nm. The original extrusion fiber texture with planes oriented parallel to extrusion direction was gradually undermined during ECAP process and eventually it was substituted by a newly stronger texture component with considerably higher intensity, coinciding with ECAP shear plane. A combination of texture modification and grain refinement in UFG samples led to a marked reduction in mechanical asymmetric behavior compared to the as-received alloy, as well as adequate mechanical properties with about 100% improvement in elongation to failure while keeping relatively high tensile strength. Open circuit potential, potentiodynamic and weight loss measurements in a phosphate buffer solution electrolyte revealed an improved corrosion resistance of UFG alloy compared to the extruded one, stemming from a shift of corrosion regime from localized pitting in the as-received sample to a more uniform corrosion mode with reduced localized attack in ECAP processed alloy. Compression tests on immersed samples showed that the rate of loss of mechanical integrity in the UFG sample was lower than that in the as-received sample.
authors: Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy.
authors: Ehsan
authors: E
authors: Mostaed
authors: Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy.
authors: Mazdak
authors: M
authors: Hashempour
authors: Department of Management and Engineering, Università di Padova, Stradella S. Nicola 3, 36100 Vicenza, Italy.
authors: Alberto
authors: A
authors: Fabrizi
authors: Department of Energy, Politecnico di Milano, 20156 Milan, Italy.
authors: David
authors: D
authors: Dellasega
authors: Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy.
authors: Massimiliano
authors: M
authors: Bestetti
authors: Department of Management and Engineering, Università di Padova, Stradella S. Nicola 3, 36100 Vicenza, Italy.
authors: Franco
authors: F
authors: Bonollo
authors: Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy.
authors: Maurizio
authors: M
authors: Vedani
mesh_terms: D000497:Alloys / Q000737:chemistry*; D019245:Compressive Strength; D003343:Corrosion; D006244:Hardness; D055595:Mechanical Phenomena; D013718:Tensile Strength
chemical_list: D000497:Alloys; C586529:ZK60 magnesium alloy
keywords: Biomaterials; Corrosion; ECAP; Texture; Ultra-fine grain; ZK60 Mg alloy