## 4 Magnesium Alloys for Biomedical Implants
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Alloying Elements** & **Biocompatibility** & **Corrosion Resistance** & **Mechanical Performance** \\ \hline Al & & Al is neurotoxic. It can cause [PERSON]’s disease and damage muscle fibers. & & It is beneficial in providing corrosion resistance. & Increases strength and plasticity. \\ Zn & & Non-cytotoxic and good biocompatibility. & & Corrosion resistance decreases with higher Zn content. & Zn participates in solid solution strengthening, increasing strength with increasing Zn content. & Zn participates in solution strengthening, increasing strength with increasing Zn content. \\ Mn & & Cytotoxic and neurotoxic. & & Provide good corrosion resistance. & It gives higher yield strength and reduces tensile strength and ductility. \\ Ca & & An essential component of human bone. & & Corrosion resistance decreases with increasing Ca content. & With increasing Ca content, strength increases, and plasticity decreases. \\ Sr & & Sr is a vital component of human bone. It also aids in bone formation. & & Corrosion resistance of Mg alloy drops with increasing Sr content. & The strength of the alloy increases with increasing Sr content. \\ Zr & & Good biocompatibility and bone-bonding ability. & & Corrosion resistance decreases with increasing Zr content. & Grains undergo refinement, increasing strength and plasticity. \\ Nd & & Cytotoxic at high concentrations but has good biosafety at low concentrations. & & Forms new phases, grain refinement, and resistance. & Ferfinement, and improvement in mechanical performance. \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Effect of alloying elements on Mg alloy performance [24]. Figure 4: Tafel plots for Magnesium alloys [64; 65; 66]. and local tissue inflammation [67; 68]. Adding aluminum (Al) in commercial magnesium (Mg) alloys is the most prominent strategy, contributing to increasing the overall corrosion resistance of Mg alloys. AE21, AZ32, and AZ91 are some examples of Al-enriched Mg alloys with remarkable mechanical and corrosion resistance properties that are used for biomedical applications. However, Al's potential in the development of [PERSON]'s disease raises concerns and underscores the requirement of intricate equilibrium in biomedical applications. Zinc (Zn), on the other hand, is vital for the human body and enhances the material strength of Mg-Al alloys. Mg-Zn alloys are highly biocompatible. Moreover, it forms protective layers that effectively slow down degradation. Mn is an essential trace element for the human body with the potential to form a protective Mn-containing oxide film that inhibits Cl-ion infiltration, rendering it a commonly employed element in Mg alloys for biomedical applications. Mg-Ca alloys favor bone implantation, reducing potential differences and improving corrosion resistance. Furthermore, Strontium (Sr) also shares chemical properties with Mg and Ca; it is found in bones and promotes bone formation. Other elements found in Mg alloys for biomedical applications include Zirconium (Zr), Silicon (Si), and Lithium (Li), which foster bone bonding and corrosion resistance and add ductility to vascular stents in biomedical applications, respectively. To summarize this section, alloying elements play a crucial role in controlling the degradation rate of magnesium alloys. The composition and concentration can be tailored to achieve the desired balance between sufficient strength for implant functionality and a degradation rate that matches the tissue healing process. The degradation rates of Mg alloys vary and determine their corrosion characteristics. Aluminum and zinc, when alloyed with magnesium, increase the oxidation rate, whereas rare earth elements decrease the oxidation rate of magnesium alloys. Combining aluminum and zinc in specific ratios yields an alloy with an overall improved performance, balanced corrosion resistance, mechanical strength, and biocompatibility [69; 70; 71].