Influence of fine‐grained structure produced by groove pressing on the properties of pure Mg and commercial ZE41 alloy

Abstract

Biodegradable metals are important for temporary implant applications. However, poor mechanical properties and higher degradation rate of Mg and its commercial alloys is a major disadvantage. In this study, the above properties were tailored using the groove pressing (GP) technique. Uniform fine-grained (UFG) pure Mg and ZE41 alloy were obtained using GP technique. The impact of GP-induced microstructural changes and surface characteristics on mechanical performance, degradation behavior, biomineralization, surface wettability, and cytocompatibility were investigated.The groove-pressed pure Mg and ZE41 alloy had grain sizes of approximately 30 ± 7.8 and 25 ± 7.5 μm, respectively. The hardness of groove-pressed pure Mg and ZE41 alloy increased by 40% and 26%, respectively, when compared to the annealed condition. Enhanced strength and elongation were observed with these samples. The potentiodynamic polarization test showed a higher E corr and lower I corr values for groove-pressed sample when compared to the annealed condition indicating decreased degradation rate. The weight loss data from immersion tests also show that the degradation rate decreases with time confirming the surface passivity of the sample. The degradation rate decreased by 37% and 44% in simulated body fluid for pure Mg and ZE41 alloy, respectively, after GP. The higher hydroxyapatite deposition on the groove-pressed sample than the annealed sample, as observed from surface morphology studies after immersion in simulated body fluid, confirms the increased biomineralization tendency after GP. The higher wettability of the groove-pressed sample leads to higher cell adhesion and cell viability when compared to the annealed sample indicating higher biocompatibility.

Enhancing the degradation rate and biomineralization nature of antiferromagnetic Fe‐20Mn alloy by groove pressing

“…The samples were preheated to 1000°C before each pass and alternately pressed between flat and grooved dies. The detailed procedure for GP has been followed from our previous paper 20 . In this study, the groove pressed, annealed, and hot rolled samples were coded as G Fe‐Mn, A Fe‐Mn, and R Fe‐Mn, respectively.…”

“…The contact angle measurements were carried out using an ACAM‐D3 contact angle goniometer (Apex, India) as per the procedure outlined earlier in our previous paper 20 …”

“…For a quantitative assessment of the percentage of viable cells, the 3‐(4,5‐dimethylthiazole‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay was used. The detailed procedure for the MTT assay is given in our previous paper 20 …”

“…The samples were sterilized with ethanol and UV irradiation (254 nm) for 1 h on each side followed by rinsed with sterile phosphate buffered saline (PBS) wash. The detailed procedure is given in our previous paper 20 …”

“…The GP process has been demonstrated to effectively modify the mechanical and biological properties of the alloys, providing a unique opportunity to precisely tune their degradation kinetics and interactions with the biological functionality 18 . The improved mechanical properties and bioactivity due to GP in Mg‐Ca alloy, 19 pure Mg and ZE41 alloy, 20 AZ31 alloy, 21 and pure titanium 22 were also reported. In Mg and its alloys GP also control the degradation rate in addition to improving the biomineralization property.…”