Abstract:Cu-containing Mg alloys are a novel type of antibacterial biomaterial based on biodegradation of Mg and antibacterial functions of Cu. However, fast degradation limits their clinical application. For the first time, this work utilizes the synergistic effects of biodegradation of ZK30, antibacterial function of Cu and grain refinement by selective laser melting (SLM) to prepare high-performance antibacterial ZK30-Cu alloys. The obtained alloys have an improved biodegradation resistance, which is attributed to r… Show more
“…The layer thickness was controlled by the Z-axial movement of the motion platform. The process parameters were optimized based on our previous work [16] and listed in Table 1. Samples with a diameter of 6 mm and a height of 5 mm were built up, with built layers set up to 100.…”
This work studied the effect of alloying Mn by selective laser melting on the microstructure and biodegradation properties of pure Mg. The grains in the microstructure were quasi-polygon in shape. The average grain size was similar (~10 μm) for the SLMed Mg-xMn with different Mn contents. The XPS spectra of the corrosion surface showed that alloying Mn into Mg by SLM produced a relatively protective manganese oxide film, which contributed to decreasing the biodegradation rate. All the results of the electrochemistry test, immersion test and the corrosion surface morphologies coincided well. The SLMed Mg-0.8Mn had the lowest biodegradation rate. When Mn content was more than 0.8 wt.%, the influence of the undissolved Mn phase on the decrease of the biodegradation resistance counteracted the influence of the relatively protective manganese oxide layer on the increase of the biodegradation resistance.
“…The layer thickness was controlled by the Z-axial movement of the motion platform. The process parameters were optimized based on our previous work [16] and listed in Table 1. Samples with a diameter of 6 mm and a height of 5 mm were built up, with built layers set up to 100.…”
This work studied the effect of alloying Mn by selective laser melting on the microstructure and biodegradation properties of pure Mg. The grains in the microstructure were quasi-polygon in shape. The average grain size was similar (~10 μm) for the SLMed Mg-xMn with different Mn contents. The XPS spectra of the corrosion surface showed that alloying Mn into Mg by SLM produced a relatively protective manganese oxide film, which contributed to decreasing the biodegradation rate. All the results of the electrochemistry test, immersion test and the corrosion surface morphologies coincided well. The SLMed Mg-0.8Mn had the lowest biodegradation rate. When Mn content was more than 0.8 wt.%, the influence of the undissolved Mn phase on the decrease of the biodegradation resistance counteracted the influence of the relatively protective manganese oxide layer on the increase of the biodegradation resistance.
“…From the point of view of production technology, these properties can be achieved through an optimized heat treatment . 23CrNi3Mo, a Cr–Ni–Mo steel, is widely used as rock drill steel at present, which can be heat‐treated to obtain a good combination of strength and toughness by austenizing, quenching, and tempering, because it contains the alloying elements such as Cr, Ni, and Mo, which promote high hardenability . However, 23CrNi3Mo rock drill tools often suffer early failure, such as brittle failure or fatigue failure even though there has been relatively little wear .…”
Section: Chemical Compositions Of the Experimental Steel (In Wt%)mentioning
This research investigates the mechanical properties of a Cr-Ni-Mo-alloyed rock drill steel tempered at different temperatures from 150 to 550 C. The highest strength, hardness, and impact energy occur when the steel is tempered at 180 C. Strength, hardness, and impact energy decrease with increasing tempering temperature from 180 to 400 C. For tempering temperatures higher than 400 C, the steel exhibits: 1) an increase in impact energy; 2) an increase in strength and hardness when tempered at 420, 450, and 480 C; and 3) a gradual decrease in strength and hardness when tempered at temperature higher than 480 C. The mechanism of the changes of impact energy and hardness with tempering temperature is proposed.
“…Furthermore, mechanical properties may be improved by alloying and grain refinement. Previous work indicated that ZK30 (Mg-3Zn-0.5Zr) had good mechanical properties and biodegradation resistance[ 13 , 23 ]. When Cu was added to ZK30 by SLM, SLMed ZK30-0.2Cu had a uniform microstructure, good cytocompatibility, and antibacterial performance[ 23 ].…”
An antibacterial biomedical Mg alloy was designed to have a low biodegradation rate. ZK30-0.2Cu-xMn (x = 0, 0.4, 0.8, 1.2, and 1.6 wt.%) was produced by selective laser melting (SLM). Alloying with Mn had a significant influence on the grain size, hardness, and biodegradation rate. Increasing Mg content to 0.8 wt% decreased the biodegradation rate, attributed to the decreased grain size and the relatively protective manganese surface oxide layer. Higher Mn contents increased the biodegradation rate attributed to the presence of the Mn-rich particles. ZK30-0.2Cu-0.8Mn exhibited the lowest biodegradation rate, strong antibacterial performance and good cytocompatibility.
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