2024 aluminum alloys were consolidated by using spark plasma sintering(SPS) method,and then heat treated by solid solution treatment(SST) and aging treatment(AT) procedures.The average grain size of bulk samples sinte...2024 aluminum alloys were consolidated by using spark plasma sintering(SPS) method,and then heat treated by solid solution treatment(SST) and aging treatment(AT) procedures.The average grain size of bulk samples sintered with 5,20 and 50 μm powders was 3.72,4.73 and 8.11 μm,respectively.The difference between the average grain size and original powder size was attributed to the recrystallization during short sintering process.The number of the inclusion phases in these samples decreased after SST and increased after subsequent AT.Besides,it was observed that intergranular corrosion(IGC) cracks initiated from stable pits due to the electrochemical inhomogeneity between the intermetallic particles(IMPs) and the aluminum matrix(176.02,110.83 and 164.80 mV for as-SPS,as-SST and as-AT samples,respectively).Besides,the cracks would propagate along the grain boundaries(GBs) and bypass the IMPs at GBs during propagation.It was revealed that the sample after SST presented the best IGC resistance,and this was ascribed to the reduce of IMPs,both in size and number.展开更多
Zinc-based alloys are promising biodegradable materials for application in the intestinal environment due to their appropriate degradation rates and favorable biocompatibility.However,the corrosion and degradation of ...Zinc-based alloys are promising biodegradable materials for application in the intestinal environment due to their appropriate degradation rates and favorable biocompatibility.However,the corrosion and degradation of biodegradable zinc alloys in the presence of intestinal microorganisms are seldom investigated.In this study,binary Zn-Mn alloys with 0.4 and 0.8 wt.%Mn content were fabricated using the extrusion process.The corrosion behaviors of pure zinc and Zn-Mn alloys with the existence of Lactobacillus acidophilus,a representative microorganism in the intestinal tract,were systematically investigated.In comparison to pure zinc,both Zn-Mn alloys exhibited enhanced strength and ductility.L.acidophilus significantly accelerated the corrosion of both pure zinc and Zn-Mn alloys by generating acidic agents.The presence of L.acidophilus increased the icorr values for pure zinc,Zn-0.4Mn,and Zn-0.8Mn from 68.7±9.9,33.9±2.3 and 17.1±0.1µA cm^(-2) to 253.5±26.7,167.6±8.7 and 30.6±2.2µA cm^(-2),respectively.The addition of Mn mitigated corrosion by refining grains and reducing the local surface potential difference.Compared to pure zinc,the surface potential difference of Zn-0.8Mn decreased from 31.8±1.7 mV to 11.8±0.9 mV.This study points out the existence of microbiologically influenced corrosion in the intestinal environment and emphasizes its importance in the comprehensive design of biodegradable zinc alloys.展开更多
基金financially supported by the National Nature Science Foundations of China (Nos.51271012 and 51671013)。
文摘2024 aluminum alloys were consolidated by using spark plasma sintering(SPS) method,and then heat treated by solid solution treatment(SST) and aging treatment(AT) procedures.The average grain size of bulk samples sintered with 5,20 and 50 μm powders was 3.72,4.73 and 8.11 μm,respectively.The difference between the average grain size and original powder size was attributed to the recrystallization during short sintering process.The number of the inclusion phases in these samples decreased after SST and increased after subsequent AT.Besides,it was observed that intergranular corrosion(IGC) cracks initiated from stable pits due to the electrochemical inhomogeneity between the intermetallic particles(IMPs) and the aluminum matrix(176.02,110.83 and 164.80 mV for as-SPS,as-SST and as-AT samples,respectively).Besides,the cracks would propagate along the grain boundaries(GBs) and bypass the IMPs at GBs during propagation.It was revealed that the sample after SST presented the best IGC resistance,and this was ascribed to the reduce of IMPs,both in size and number.
基金financially supported by the National Natural Science Foundation of China(No.52231010).
文摘Zinc-based alloys are promising biodegradable materials for application in the intestinal environment due to their appropriate degradation rates and favorable biocompatibility.However,the corrosion and degradation of biodegradable zinc alloys in the presence of intestinal microorganisms are seldom investigated.In this study,binary Zn-Mn alloys with 0.4 and 0.8 wt.%Mn content were fabricated using the extrusion process.The corrosion behaviors of pure zinc and Zn-Mn alloys with the existence of Lactobacillus acidophilus,a representative microorganism in the intestinal tract,were systematically investigated.In comparison to pure zinc,both Zn-Mn alloys exhibited enhanced strength and ductility.L.acidophilus significantly accelerated the corrosion of both pure zinc and Zn-Mn alloys by generating acidic agents.The presence of L.acidophilus increased the icorr values for pure zinc,Zn-0.4Mn,and Zn-0.8Mn from 68.7±9.9,33.9±2.3 and 17.1±0.1µA cm^(-2) to 253.5±26.7,167.6±8.7 and 30.6±2.2µA cm^(-2),respectively.The addition of Mn mitigated corrosion by refining grains and reducing the local surface potential difference.Compared to pure zinc,the surface potential difference of Zn-0.8Mn decreased from 31.8±1.7 mV to 11.8±0.9 mV.This study points out the existence of microbiologically influenced corrosion in the intestinal environment and emphasizes its importance in the comprehensive design of biodegradable zinc alloys.
