Effects of Dy Addition on the Mechanical and Degradation Properties of Mg–2Zn–0.5Zr Alloy. Issue 4 (18th February 2020)

• Record Type: Journal Article
• Authors: Li, Huan; Wen, Jiuba; He, Junguang; Shi, Huina; Liu, Ya
• Is Part Of: Advanced engineering materials. Volume 22:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-02-18
• Subjects: biodegradation properties -- biomagnesium alloys -- mechanical properties; Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.201901360
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : As candidates for biomaterials, magnesium and its alloys have promising properties such as biodegradability and biocompatibility. However, their poor mechanical properties and rapid degradation rate limit clinical application; therefore, solving these issues is essential for practical application. Herein, different contents of dysprosium (Dy) (0, 0.5, 1, 1.5, 2, 3 mass%) are added to the Mg–2Zn–0.5Zr biomagnesium alloy to explore its effect on the mechanical and degradation properties. Assessments are conducted using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), immersion, and electrode chemical experiments. The results indicate that the addition of Dy significantly decreases the grain size, and the second phase is (Mg, Dy)7 Zn3 with a body‐centered cubic structure. At a Dy content of 1.5 mass%, grain refinement and second‐phase strengthening result in the alloy having relatively good properties, with an ultimate tensile strength (UTS) = 150 ± 14 MPa, yield strength (YS) = 89 ± 3 MPa, and elongation (EL) = 9.2 ± 0.6%. The addition of Dy promotes the formation of a stable protective film and increases the electrode potential of the Mg matrix, resulting in a degradation rate of 0.89 ± 0.12 mm year −1 . The results indicate that the alloy with 1.5 mass% Dy content is a promising candidate for using as a biodegradable material. Abstract : Fine granular and network secondary phases are appeared when the Dy content exceeds 1.5 mass%. Furthermore, the fine granular second phase accompanied with cracks propagation facilitates dimples formation. However, the network second phase promotes cracks formation and propagation. In addition, the network second phase causes severe local corrosion.