Abstract Considering the biocompatibility and biosafety of the alloying elements, Mg-Zn-Ca alloys are the most promising biodegradable metallic biomaterials for orthopedic applications. However, their composition and microstructure need to be optimized so as to obtain desirable performance. In this work, the microstructure, mechanical properties and corrosion resistance of five as-extruded Mg-4Zn-xCa (x = 0, 0.1, 0.3, 0.5, 0.8 wt%) alloys were investigated systematically in order to find the optimal Ca content. The microstructure of Mg-4Zn binary alloy consisted of α–Mg matrix and MgZn secondary phase particles that was replaced by Ca2Mg6Zn3 in the ternary alloys. A well-defined orientation relationship between Ca2Mg6Zn3 and the matrix was identified to be (01 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\overline{1 }$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 2)Mg//(01 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\overline{1 }$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 0)Ca2Mg6Zn3, (01 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\overline{1 }\overline{2 }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mover> <mn>2</mn> <mo>¯</mo> </mover> </mrow> </math></EquationSource> </InlineEquation>)Mg//(0001)Ca2Mg6Zn3, and [2 <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\overline{1 }\overline{1 }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mover> <mn>1</mn> <mo>¯</mo> </mover> </mrow> </math></EquationSource> </InlineEquation> 0]Mg//[<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$\overline{2 }$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>2</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 110]Ca2Mg6Zn3, and a planar interface parallel to (10 <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$\overline{1 }$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 1)Mg and (10 <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$\overline{1 }$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 0)Ca2Mg6Zn3 was determined as well. Alloying with different content of Ca refined the grains and improved the yield strength (YS) and ultimate tensile strength (UTS) progressively. But the elongation showed a tendency of increase and then decrease with Ca content. Also, the corrosion resistance in simulated body fluid of Mg-4Zn-xCa alloys exhibited a non-monotonic variation with the increasing Ca content. The effect of Ca content on the mechanical and corrosion properties was discussed mainly based on the grain size and number of particles. Considering the mechanical properties and corrosion resistance comprehensively, as-extruded Mg-4Zn-0.5Ca is proposed to be the most promising candidate for biomedical application. Graphical Abstract

Effect of Ca Content on the Microstructure, Mechanical Properties and Corrosion Resistance of As-Extruded Mg-4Zn-xCa Alloys

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发表日期：

2025年6月27日

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Yi Chen,
Ting He,
Xiuhong Li,
Liying Qiao,
Hongfeng Yuan,
Jiayan Yi,
Yong Wang

摘要

Abstract

Considering the biocompatibility and biosafety of the alloying elements, Mg-Zn-Ca alloys are the most promising biodegradable metallic biomaterials for orthopedic applications. However, their composition and microstructure need to be optimized so as to obtain desirable performance. In this work, the microstructure, mechanical properties and corrosion resistance of five as-extruded Mg-4Zn-xCa (x = 0, 0.1, 0.3, 0.5, 0.8 wt%) alloys were investigated systematically in order to find the optimal Ca content. The microstructure of Mg-4Zn binary alloy consisted of α–Mg matrix and MgZn secondary phase particles that was replaced by Ca₂Mg₆Zn₃ in the ternary alloys. A well-defined orientation relationship between Ca₂Mg₆Zn₃ and the matrix was identified to be (01 $\overline{1 }$ $\bar{1}$ 2)_Mg//(01 $\overline{1 }$ $\bar{1}$ 0)_Ca2Mg6Zn3, (01 $\overline{1 }\overline{2 }$ $\bar{1} \bar{2}$ )_Mg//(0001)_Ca2Mg6Zn3, and [2 $\overline{1 }\overline{1 }$ $\bar{1} \bar{1}$ 0]_Mg//[ $\overline{2 }$ $\bar{2}$ 110]_Ca2Mg6Zn3, and a planar interface parallel to (10 $\overline{1 }$ $\bar{1}$ 1)_Mg and (10 $\overline{1 }$ $\bar{1}$ 0)_Ca2Mg6Zn3 was determined as well. Alloying with different content of Ca refined the grains and improved the yield strength (YS) and ultimate tensile strength (UTS) progressively. But the elongation showed a tendency of increase and then decrease with Ca content. Also, the corrosion resistance in simulated body fluid of Mg-4Zn-xCa alloys exhibited a non-monotonic variation with the increasing Ca content. The effect of Ca content on the mechanical and corrosion properties was discussed mainly based on the grain size and number of particles. Considering the mechanical properties and corrosion resistance comprehensively, as-extruded Mg-4Zn-0.5Ca is proposed to be the most promising candidate for biomedical application.

Graphical Abstract