Hot deformation behaviors and microstructure evolution of Ti-3Al-5Mo-4Cr-2Zr-1Fe(Ti-35421)alloy in theβsingle field are investigated by isothermal compression tests on a Gleeble-3500 simulator at temperatures of 820-...Hot deformation behaviors and microstructure evolution of Ti-3Al-5Mo-4Cr-2Zr-1Fe(Ti-35421)alloy in theβsingle field are investigated by isothermal compression tests on a Gleeble-3500 simulator at temperatures of 820-900°C and strain rates of 0.001-1 s^(-1).The research results show that discontinuous yield phenomenon and rheological softening are affected by the strain rates and deformation temperatures.The critical conditions for dynamic recrystallization and kinetic model of Ti-35421 alloy are determined,and the Arrhenius constitutive model is constructed.The rheological behaviors of Ti-35421 alloys aboveβphase transformation temperature are predicted by the constitutive model accurately.The EBSD analysis proves that the deformation softening is controlled by dynamic recovery and dynamic recrystallization.In addition,continuous dynamic recrystallization is determined during hot deformation,and the calculation model for recrystallization grain sizes is established.Good linear dependency between the experimental and simulated values of recrystallized grain sizes indicates that the present model can be used for the prediction of recrystallized grain size with high accuracy.展开更多
In this research, corrosion behavior, mechanical properties and bioactivity of Ti–Zr–Cu–Pd–Sn bulk metallic glasses with minor addition of Au, Pt, Nb or Ta elements were investigated. The results revealed that min...In this research, corrosion behavior, mechanical properties and bioactivity of Ti–Zr–Cu–Pd–Sn bulk metallic glasses with minor addition of Au, Pt, Nb or Ta elements were investigated. The results revealed that minor additions of the elements were beneficial to enhancing mechanical properties and corrosion resistance of Ti-based bulk metallic glasses.Minor addition of the element（especially with Nb and Ta addition） results in the improvement in plastic deformation ability due to the existing of nanoparticles with a size smaller than 10 nm in glassy matrix, inhibiting the deformation of the shear bonds. Enrichments of Ti and Zr elements in oxide layer were responsible for high corrosion resistance. The bioactivity of Ti-based bulk metallic glasses was also investigated. The best combination of large plastic deformation ability, good corrosion resistance and bioactivity in Ti40Zr10Cu33Pd（14）Sn2Ta1 BMG was obtained.展开更多
Centimeter-sized Mg65Zn30Ca5 bulk amorphous alloys were fabricated by the spark plasma sintering process from the amorphous powders with a size smaller than 5 la m prepared by ball-milling. The sintered Mg65Zn30Ca5 sa...Centimeter-sized Mg65Zn30Ca5 bulk amorphous alloys were fabricated by the spark plasma sintering process from the amorphous powders with a size smaller than 5 la m prepared by ball-milling. The sintered Mg65Zn30Ca5 samples were in an amorphous state when the spark plasma sintering was performed at a temperature of 383 K under a pressure of 600 MPa. The data of polarization curves presented that the sintered Mg65Zn30Ca5 bulk amorphous alloys exhibited higher corrosion resistance than pure Mg and AZ31B alloy owing to high content of Zn and homogeneous structure. A calcium phosphate compound layer was formed on the sintered Mg65Zn30Ca5 bulk amorphous sample after immersion in Hanks＇ solution, which is effective in improving corrosion resistance and bioactivity. The sintered MgZnCa bulk amorphous alloys with large dimensions broaden the potential application of bulk amorphous alloys in the biomedical fields.展开更多
Surface Ag granular packs(SAgPs) have been fabricated from dual-phase Ag_(35.5)Zn_(64.5) precursor alloy consisting of both e and c phases by using a facile one-step triangle wave potential cycling in 0.5 mol·L^(...Surface Ag granular packs(SAgPs) have been fabricated from dual-phase Ag_(35.5)Zn_(64.5) precursor alloy consisting of both e and c phases by using a facile one-step triangle wave potential cycling in 0.5 mol·L^(-1) KOH.During the continuous potential cyclic sweeping, the c phases preferentially dissolve during the anodic scan and dominant reduction reactions of Ag cations lead to redeposition and accumulation of Ag atoms together to form SAg Ps during cathodic scan. The e phases stay inactive to form a continuous skeleton in the inner regions. SAg Ps with an average particle size of 94-129 nm can be obtained at scan rates of 25, 50 and 100 mV·s^(-1) for 100 triangle wave potential cycles. SAgPs formed at a scan rate of 50 mV·s^(-1) exhibit superior oxygen reduction reaction performances with the onset potential of 0.93 V, half-wave potential of 0.72 V and an electron transfer number of 4.0.The above-mentioned SAgPs have superior stabilities as ORR catalysts.展开更多
In this paper, we report the fabrication of the photocatalysts composed of Cu_2O nanobelts and nanoporous Cu(NP Cu)substrate, which is obtained by soaking the NP Cu in dehydrated ethanol. The NP Cu substrate is achiev...In this paper, we report the fabrication of the photocatalysts composed of Cu_2O nanobelts and nanoporous Cu(NP Cu)substrate, which is obtained by soaking the NP Cu in dehydrated ethanol. The NP Cu substrate is achieved by dealloying of Ti_(40.6)Zr_(9.4)Cu_(40.6)Ni_(6.3)Sn_(3.1) amorphous ribbons in HF solutions. The dealloying process is considered to be a thermally activated process, obeying the Arrhenius law. The surface diffusivity increases with increasing dealloying temperature and concentration of HF solutions. The activation energy of the diffusion of Cu adatoms is estimated to be 76.4 kJ/mol. The Cu_2O nanobelts with the width of 10–15 nm and the length of about 1 lm are formed on the surface of NP Cu after immersion in dehydrated ethanol. The photocatalysts of Cu_2O on nanoporous Cu exhibit superior photocatalytic activity toward the degradation of methyl orange and methylene blue under the irradiation of the sunlight due to the coexistence of Cu_2O semiconductor nanobelts and large amount of heterojunctions as flowing path for photoelectrons.展开更多
基金the financial supports from the National Natural Science Foundation of China (Nos. 52001163, 52075237)the Primary Research and Development Plan of Jiangsu Province, China (No. BE2019119)
文摘Hot deformation behaviors and microstructure evolution of Ti-3Al-5Mo-4Cr-2Zr-1Fe(Ti-35421)alloy in theβsingle field are investigated by isothermal compression tests on a Gleeble-3500 simulator at temperatures of 820-900°C and strain rates of 0.001-1 s^(-1).The research results show that discontinuous yield phenomenon and rheological softening are affected by the strain rates and deformation temperatures.The critical conditions for dynamic recrystallization and kinetic model of Ti-35421 alloy are determined,and the Arrhenius constitutive model is constructed.The rheological behaviors of Ti-35421 alloys aboveβphase transformation temperature are predicted by the constitutive model accurately.The EBSD analysis proves that the deformation softening is controlled by dynamic recovery and dynamic recrystallization.In addition,continuous dynamic recrystallization is determined during hot deformation,and the calculation model for recrystallization grain sizes is established.Good linear dependency between the experimental and simulated values of recrystallized grain sizes indicates that the present model can be used for the prediction of recrystallized grain size with high accuracy.
基金financially supported by the Natural Science Foundation of China (Grant No. 51301091)the Natural Science Foundation of Jiangsu Province (Grant No. BK20151536)the Fundamental Research Funds for the Central Universities (Grant No. AE16001)
文摘In this research, corrosion behavior, mechanical properties and bioactivity of Ti–Zr–Cu–Pd–Sn bulk metallic glasses with minor addition of Au, Pt, Nb or Ta elements were investigated. The results revealed that minor additions of the elements were beneficial to enhancing mechanical properties and corrosion resistance of Ti-based bulk metallic glasses.Minor addition of the element（especially with Nb and Ta addition） results in the improvement in plastic deformation ability due to the existing of nanoparticles with a size smaller than 10 nm in glassy matrix, inhibiting the deformation of the shear bonds. Enrichments of Ti and Zr elements in oxide layer were responsible for high corrosion resistance. The bioactivity of Ti-based bulk metallic glasses was also investigated. The best combination of large plastic deformation ability, good corrosion resistance and bioactivity in Ti40Zr10Cu33Pd（14）Sn2Ta1 BMG was obtained.
基金financially supported by the Natural Science Foundation of China under Grant No. 51301091the Natural Science Foundation of Jiangsu Province Grant No. BK20151536+1 种基金the Fundamental Research Funds for the Central Universities No. AE16001the Advanced Materials Development and Integration of Novel Structured Metallic and Inorganic Materials from the Ministry of Education, Sport, Culture, Science and Technology, Japan
文摘Centimeter-sized Mg65Zn30Ca5 bulk amorphous alloys were fabricated by the spark plasma sintering process from the amorphous powders with a size smaller than 5 la m prepared by ball-milling. The sintered Mg65Zn30Ca5 samples were in an amorphous state when the spark plasma sintering was performed at a temperature of 383 K under a pressure of 600 MPa. The data of polarization curves presented that the sintered Mg65Zn30Ca5 bulk amorphous alloys exhibited higher corrosion resistance than pure Mg and AZ31B alloy owing to high content of Zn and homogeneous structure. A calcium phosphate compound layer was formed on the sintered Mg65Zn30Ca5 bulk amorphous sample after immersion in Hanks＇ solution, which is effective in improving corrosion resistance and bioactivity. The sintered MgZnCa bulk amorphous alloys with large dimensions broaden the potential application of bulk amorphous alloys in the biomedical fields.
基金financially supported by the State Key Laboratory of Advanced Metals and Materials (No.2018-ZD04)the State Key Laboratory of Metal Material for Marine Equipment and Application (No. SKLMEA-K201806)+2 种基金the Natural Science Foundation of China (Nos. 51671106 and 51931008)the Natural Science Foundation of Jiangsu Province (Nos. BK20171424and BE2019119)the National Defense Basic Scientific Research Program of China (No. JCKY08414C020)。
文摘Surface Ag granular packs(SAgPs) have been fabricated from dual-phase Ag_(35.5)Zn_(64.5) precursor alloy consisting of both e and c phases by using a facile one-step triangle wave potential cycling in 0.5 mol·L^(-1) KOH.During the continuous potential cyclic sweeping, the c phases preferentially dissolve during the anodic scan and dominant reduction reactions of Ag cations lead to redeposition and accumulation of Ag atoms together to form SAg Ps during cathodic scan. The e phases stay inactive to form a continuous skeleton in the inner regions. SAg Ps with an average particle size of 94-129 nm can be obtained at scan rates of 25, 50 and 100 mV·s^(-1) for 100 triangle wave potential cycles. SAgPs formed at a scan rate of 50 mV·s^(-1) exhibit superior oxygen reduction reaction performances with the onset potential of 0.93 V, half-wave potential of 0.72 V and an electron transfer number of 4.0.The above-mentioned SAgPs have superior stabilities as ORR catalysts.
基金financially supported by the National Natural Science Foundation of China under Grant No. 51671106the Natural Science Foundation of Jiangsu Province under Grant Nos. BK20171424 and BK2015153
文摘In this paper, we report the fabrication of the photocatalysts composed of Cu_2O nanobelts and nanoporous Cu(NP Cu)substrate, which is obtained by soaking the NP Cu in dehydrated ethanol. The NP Cu substrate is achieved by dealloying of Ti_(40.6)Zr_(9.4)Cu_(40.6)Ni_(6.3)Sn_(3.1) amorphous ribbons in HF solutions. The dealloying process is considered to be a thermally activated process, obeying the Arrhenius law. The surface diffusivity increases with increasing dealloying temperature and concentration of HF solutions. The activation energy of the diffusion of Cu adatoms is estimated to be 76.4 kJ/mol. The Cu_2O nanobelts with the width of 10–15 nm and the length of about 1 lm are formed on the surface of NP Cu after immersion in dehydrated ethanol. The photocatalysts of Cu_2O on nanoporous Cu exhibit superior photocatalytic activity toward the degradation of methyl orange and methylene blue under the irradiation of the sunlight due to the coexistence of Cu_2O semiconductor nanobelts and large amount of heterojunctions as flowing path for photoelectrons.
