The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behavior...The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.展开更多
As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a...As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a small number of edge sites only,while the basal plane is catalytically inert.Herein,we report that boron(B)doped 1T phase MoS_(2) NSs can replace precious metals as a co-catalyst to assist in photocatalytic H_(2) production of 2D layered g-C_(3)N_(4) nanosheets(g-C_(3)N_(4) NSs).The H_(2) evolution rate of prepared B-MoS_(2)@g-C_(3)N_(4) composites with 15 wt%B-MoS_(2)(B-MoS_(2)@g-C_(3)N_(4)–15,1612.75μmol h^(−1) g^(−1))is 52.33 times of pure g-C_(3)N_(4) NSs(30.82μmol h^(−1) g^(−1)).Furthermore,the apparent quantum efficiency(AQE)of B-MoS_(2)@g-C_(3)N_(4)–15 composites under the light atλ=370 nm is calculated and reaches 5.54%.The excellent photocatalytic performance of B-MoS_(2)@g-C_(3)N_(4)–15 composites is attributed to the B ions doping inducing the distortion of 1T phase MoS_(2) crystal,which can activate more base planes to offer more active sites for H_(2) evolution reaction(HER).This work of B-MoS_(2)@g-C_(3)N_(4) composites offers experience in the progress of effective and low-price photocatalysts for HER.展开更多
The effects of aging on the microstructure, mechanical properties, intergranular corrosion, and exfoliation corrosion of an Al-3.5Cu-1.5Li-0.22（Sc ＋ Zr） alloy have been investigated. The results show that the alloy...The effects of aging on the microstructure, mechanical properties, intergranular corrosion, and exfoliation corrosion of an Al-3.5Cu-1.5Li-0.22（Sc ＋ Zr） alloy have been investigated. The results show that the alloy has the character of age hardening, and the major phase of precipitation and strengthening is the T1 phase. The aging temperature and aging time have a significant effect on the amount and distribution of the T1 phase. The proper artificial single-aging treatment of the alloy is at 160℃ for 40 h. The intergranular corrosion and exfoliation corrosion of the alloy are caused by the anodic dissolution of the T1 phase and the precipitate-free zone （PFZ）. With increasing the aging time to overaged, the T1 phase coarsens, and the PFZ widens, leading to an increase in the susceptibility to intergranular corrosion and exfoliation corrosion.展开更多
The precipitation behaviors of an A1-Cu-Li-Mn-Zr alloy at different ageing temperatures （120, 160 and 200 ~C） were investigated using Vickers hardness measurements and transmission electron microscopy （TEM） charac...The precipitation behaviors of an A1-Cu-Li-Mn-Zr alloy at different ageing temperatures （120, 160 and 200 ~C） were investigated using Vickers hardness measurements and transmission electron microscopy （TEM） characterization. Age hardening curves show an increase in precipitation kinetics with increasing ageing temperature. The results of TEM show that for the samples peak aged at 120 ~C, the amount of g＇ （A13Li）, GP zones/0＇ （A12Cu） and Z （A15Cu6Li2） phases is obviously higher than that of T1 （A12CuLi） precipitates; while the samples peak aged at 160 and 200 ~C are usually dominated by T1 phase with a minor fraction of GP zones/0＇ and g＇, and the Z phase almost does not form. In addition, quantitative analysis on the T1 platelets demonstrates that the samples peak aged at 200 ~C have larger plate diameter and smaller area fraction of T1, as compared to the samples peak aged at 160 ~C. Correspondingly, the possible reasons for such phenomena are discussed.展开更多
基金financially supported by the National Key Research and Development Program of China (No. 2019YFA0708801)the National Natural Science Foundation of China (No. 51875125)。
文摘The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.
基金fundings from the National Natural Science Foundation of China(No.51872173)Taishan Scholars Program of Shandong Province(No.tsqn201812068)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2022JQ21)Higher School Youth Innovation Team of Shandong Province(No.2019KJA013).
文摘As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a small number of edge sites only,while the basal plane is catalytically inert.Herein,we report that boron(B)doped 1T phase MoS_(2) NSs can replace precious metals as a co-catalyst to assist in photocatalytic H_(2) production of 2D layered g-C_(3)N_(4) nanosheets(g-C_(3)N_(4) NSs).The H_(2) evolution rate of prepared B-MoS_(2)@g-C_(3)N_(4) composites with 15 wt%B-MoS_(2)(B-MoS_(2)@g-C_(3)N_(4)–15,1612.75μmol h^(−1) g^(−1))is 52.33 times of pure g-C_(3)N_(4) NSs(30.82μmol h^(−1) g^(−1)).Furthermore,the apparent quantum efficiency(AQE)of B-MoS_(2)@g-C_(3)N_(4)–15 composites under the light atλ=370 nm is calculated and reaches 5.54%.The excellent photocatalytic performance of B-MoS_(2)@g-C_(3)N_(4)–15 composites is attributed to the B ions doping inducing the distortion of 1T phase MoS_(2) crystal,which can activate more base planes to offer more active sites for H_(2) evolution reaction(HER).This work of B-MoS_(2)@g-C_(3)N_(4) composites offers experience in the progress of effective and low-price photocatalysts for HER.
基金This work was financially supported by the National High-Tech Research and Development Program of China (No.2006AA03Z523).
文摘The effects of aging on the microstructure, mechanical properties, intergranular corrosion, and exfoliation corrosion of an Al-3.5Cu-1.5Li-0.22（Sc ＋ Zr） alloy have been investigated. The results show that the alloy has the character of age hardening, and the major phase of precipitation and strengthening is the T1 phase. The aging temperature and aging time have a significant effect on the amount and distribution of the T1 phase. The proper artificial single-aging treatment of the alloy is at 160℃ for 40 h. The intergranular corrosion and exfoliation corrosion of the alloy are caused by the anodic dissolution of the T1 phase and the precipitate-free zone （PFZ）. With increasing the aging time to overaged, the T1 phase coarsens, and the PFZ widens, leading to an increase in the susceptibility to intergranular corrosion and exfoliation corrosion.
基金Project（2016YFB0300901） supported by the National Key R＆D Program of China Project（51421001） supported by the National Natural Science Foundation of China Project（2018CDJDCL0019） supported by the Fundamental Research Funds for the Central Universities, China
文摘The precipitation behaviors of an A1-Cu-Li-Mn-Zr alloy at different ageing temperatures （120, 160 and 200 ~C） were investigated using Vickers hardness measurements and transmission electron microscopy （TEM） characterization. Age hardening curves show an increase in precipitation kinetics with increasing ageing temperature. The results of TEM show that for the samples peak aged at 120 ~C, the amount of g＇ （A13Li）, GP zones/0＇ （A12Cu） and Z （A15Cu6Li2） phases is obviously higher than that of T1 （A12CuLi） precipitates; while the samples peak aged at 160 and 200 ~C are usually dominated by T1 phase with a minor fraction of GP zones/0＇ and g＇, and the Z phase almost does not form. In addition, quantitative analysis on the T1 platelets demonstrates that the samples peak aged at 200 ~C have larger plate diameter and smaller area fraction of T1, as compared to the samples peak aged at 160 ~C. Correspondingly, the possible reasons for such phenomena are discussed.
