激光粉末床熔融(Laser Powder Bed Fusion,LPBF)技术是定制化多孔纯Mo结构的重要技术。然而,LPBF成形纯Mo试样仍面临表面粗糙度值高及耐蚀性差等问题。电化学抛光(Electrochemical Polishing,ECP)是LPBF成形纯Mo的主要环保型后处理工艺...激光粉末床熔融(Laser Powder Bed Fusion,LPBF)技术是定制化多孔纯Mo结构的重要技术。然而,LPBF成形纯Mo试样仍面临表面粗糙度值高及耐蚀性差等问题。电化学抛光(Electrochemical Polishing,ECP)是LPBF成形纯Mo的主要环保型后处理工艺。研究了不同ECP抛光状态对LPBF成形纯Mo的表面粗糙度及降解特性的影响。结果表明:经电化学抛光处理后,试样表面粗糙度由4.55μm显著降低至1.05μm;相比原始态试样,抛光后试样腐蚀电流密度降低了78.4%。失重率从大到小顺序为:原始态>半抛光>抛光,且随着浸泡时间增加,失重率逐渐增加。溶液pH值波动≤0.5,验证了降解过程未引发局部酸化,符合生物医用材料要求。通过采用ECP处理Mo基材料表面,为合理调控其植入体的降解行为及降解速率的均匀性提供了重要理论依据。展开更多
The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf ...The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf increases the average diameter ofγ'phases after thermal exposure at 700℃ for 5000 h,which enhances the critical resolved shear stress required for dislocations to shear the γ'phases in the Ni-Cr-Mo alloy.Simultaneously,element Hf incorporated into the γ'phases increases the lattice mismatch between the γ'and γ phase,thereby strengthening the coherency strengthening effect.These two factors collectively contribute to the enhanced strength of the alloy.Thus,Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700℃.展开更多
In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show th...In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show that the sample is brittle when direct aging(A)is applied at 350℃for 1 h after solution treatment(ST).If pre-deformation(D)is performed on the ST sample to induce{332}twins and secondaryα″phase,subsequent aging at 350℃(STDA350)improves the strength to 931 MPa with a good ductility of about 20%maintained.However,when aging is performed at 400℃or 450℃(STDA400/450),the strength can be further improved,but the ductility is dramatically reduced.Atomic-scale characterizations show that the partial collapse ofωphase in the STDA350 sample effectively eliminates aging-induced embrittlement,but complete collapse leads to poor ductility in the STDA400/450 sample.展开更多
^(99)Mo是重要的医用放射性核素,溶剂萃取法是反应堆辐照^(235)U靶生产裂变^(99)Mo的分离方法之一。为探讨离子液体Cyphos IL 101用于裂变^(99)Mo分离的可能性,本研究评价了离子液体Cyphos IL 101在硝酸体系中对Mo(Ⅵ)的萃取行为,重点...^(99)Mo是重要的医用放射性核素,溶剂萃取法是反应堆辐照^(235)U靶生产裂变^(99)Mo的分离方法之一。为探讨离子液体Cyphos IL 101用于裂变^(99)Mo分离的可能性,本研究评价了离子液体Cyphos IL 101在硝酸体系中对Mo(Ⅵ)的萃取行为,重点考察了稀释剂、水相初始pH、萃取时间、温度、离子液体浓度等对萃取Mo(Ⅵ)的影响。结果表明,选用甲苯作为稀释剂时,Cyphos IL 101对Mo(Ⅵ)的萃取效果最好,在pH=3条件下,萃取率高达98.87%;萃取为自发进行的过程,且可在5 min达到平衡;选用1 mol/L Na_(2)CO_(3)作为反萃剂,一次反萃可将负载有机相中96.56%的Mo反萃到水相中。构建的离子液体Cyphos IL 101萃取体系对Mo与主要杂质Sr、Cs、Te等有很好的分离效果,体现了其对Mo(Ⅵ)的高选择性萃取能力。以上结果可为将离子液体Cyphos IL 101引入裂变^(99)Mo的分离工艺流程提供参考。展开更多
Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages ...Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages of amorphous materials to optimize the interfacial structure for efficient Na^(+)storage.Herein,the dense homologous amorphous/crystalline heterointerfaces are in situ achieved in N-doped carbon nanobundles via self-polymerization and precise nitriding(Mo–N/Mo_(2)N@C).The amorphous Mo–N rich in unsaturated vacancy defects provides abundant active sites with isotropic ion-transport channels,and can effectively alleviate structural stress from crystalline Mo_(2)N.Meanwhile,the conductive Mo_(2)N can facilitate effective electron transfer,augmented further by the carbon encapsulation.Theoretical calculations reveal that the dense heterointerfaces can optimize the electronic structure and shift the d-p orbital centers of Mo and N upward,thereby enhancing the adsorption and mobility of Na^(+),and ultimately improving the charge transport and storage efficiency of the electrode.The Mo–N/Mo_(2)N@C as an anode delivers a 46.9%increase in reversible capacity over Mo_(2)N@C,reaching 461.1 m Ah.g^(–1)at 0.1 A.g^(–1),along with improved rate capability and cycling stability,underlining its practical utility.These results suggest that the homologous interfacial coupling can boost the storage properties of nitrides,providing a valuable reference for improving the properties of electrodes with low theoretical capacities.展开更多
文摘激光粉末床熔融(Laser Powder Bed Fusion,LPBF)技术是定制化多孔纯Mo结构的重要技术。然而,LPBF成形纯Mo试样仍面临表面粗糙度值高及耐蚀性差等问题。电化学抛光(Electrochemical Polishing,ECP)是LPBF成形纯Mo的主要环保型后处理工艺。研究了不同ECP抛光状态对LPBF成形纯Mo的表面粗糙度及降解特性的影响。结果表明:经电化学抛光处理后,试样表面粗糙度由4.55μm显著降低至1.05μm;相比原始态试样,抛光后试样腐蚀电流密度降低了78.4%。失重率从大到小顺序为:原始态>半抛光>抛光,且随着浸泡时间增加,失重率逐渐增加。溶液pH值波动≤0.5,验证了降解过程未引发局部酸化,符合生物医用材料要求。通过采用ECP处理Mo基材料表面,为合理调控其植入体的降解行为及降解速率的均匀性提供了重要理论依据。
基金National Key Research and Development Program of China(2021YFB3704103)National Natural Science Foundation of China(51571191)。
文摘The influence of Hf on the precipitation behavior of γ'phase and the subsequent tensile properties of a Ni-Cr-Mo alloy after long-term thermal exposure was investigated.The results reveal that the addition of Hf increases the average diameter ofγ'phases after thermal exposure at 700℃ for 5000 h,which enhances the critical resolved shear stress required for dislocations to shear the γ'phases in the Ni-Cr-Mo alloy.Simultaneously,element Hf incorporated into the γ'phases increases the lattice mismatch between the γ'and γ phase,thereby strengthening the coherency strengthening effect.These two factors collectively contribute to the enhanced strength of the alloy.Thus,Hf alloying effectively improves the yield strength of the Ni-Cr-Mo alloy after thermal exposure at 700℃.
基金the financial support from the National Natural Science Foundation of China (No. 52374380)the China Postdoctoral Science Foundation (Nos. 2023M730234, 2024T171126)。
文摘In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show that the sample is brittle when direct aging(A)is applied at 350℃for 1 h after solution treatment(ST).If pre-deformation(D)is performed on the ST sample to induce{332}twins and secondaryα″phase,subsequent aging at 350℃(STDA350)improves the strength to 931 MPa with a good ductility of about 20%maintained.However,when aging is performed at 400℃or 450℃(STDA400/450),the strength can be further improved,but the ductility is dramatically reduced.Atomic-scale characterizations show that the partial collapse ofωphase in the STDA350 sample effectively eliminates aging-induced embrittlement,but complete collapse leads to poor ductility in the STDA400/450 sample.
文摘^(99)Mo是重要的医用放射性核素,溶剂萃取法是反应堆辐照^(235)U靶生产裂变^(99)Mo的分离方法之一。为探讨离子液体Cyphos IL 101用于裂变^(99)Mo分离的可能性,本研究评价了离子液体Cyphos IL 101在硝酸体系中对Mo(Ⅵ)的萃取行为,重点考察了稀释剂、水相初始pH、萃取时间、温度、离子液体浓度等对萃取Mo(Ⅵ)的影响。结果表明,选用甲苯作为稀释剂时,Cyphos IL 101对Mo(Ⅵ)的萃取效果最好,在pH=3条件下,萃取率高达98.87%;萃取为自发进行的过程,且可在5 min达到平衡;选用1 mol/L Na_(2)CO_(3)作为反萃剂,一次反萃可将负载有机相中96.56%的Mo反萃到水相中。构建的离子液体Cyphos IL 101萃取体系对Mo与主要杂质Sr、Cs、Te等有很好的分离效果,体现了其对Mo(Ⅵ)的高选择性萃取能力。以上结果可为将离子液体Cyphos IL 101引入裂变^(99)Mo的分离工艺流程提供参考。
基金financially supported by the National Natural Science Foundation of China(No.51762021)the Natural Science Foundation of Jiangxi province(Nos.20224ACB204008,20242BAB25223,and 20242BAB25248)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594)。
文摘Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages of amorphous materials to optimize the interfacial structure for efficient Na^(+)storage.Herein,the dense homologous amorphous/crystalline heterointerfaces are in situ achieved in N-doped carbon nanobundles via self-polymerization and precise nitriding(Mo–N/Mo_(2)N@C).The amorphous Mo–N rich in unsaturated vacancy defects provides abundant active sites with isotropic ion-transport channels,and can effectively alleviate structural stress from crystalline Mo_(2)N.Meanwhile,the conductive Mo_(2)N can facilitate effective electron transfer,augmented further by the carbon encapsulation.Theoretical calculations reveal that the dense heterointerfaces can optimize the electronic structure and shift the d-p orbital centers of Mo and N upward,thereby enhancing the adsorption and mobility of Na^(+),and ultimately improving the charge transport and storage efficiency of the electrode.The Mo–N/Mo_(2)N@C as an anode delivers a 46.9%increase in reversible capacity over Mo_(2)N@C,reaching 461.1 m Ah.g^(–1)at 0.1 A.g^(–1),along with improved rate capability and cycling stability,underlining its practical utility.These results suggest that the homologous interfacial coupling can boost the storage properties of nitrides,providing a valuable reference for improving the properties of electrodes with low theoretical capacities.
