Fe-Al-Ta eutectic composites with solidification rates of 6,20,30,80 and 200μm/s were obtained by a modified Bridgman directional solidification technique and alloying.Moreover,tensile property and fracture behavior ...Fe-Al-Ta eutectic composites with solidification rates of 6,20,30,80 and 200μm/s were obtained by a modified Bridgman directional solidification technique and alloying.Moreover,tensile property and fracture behavior of Fe-Al-Ta eutectic composites were studied at 600℃.The relationship between mechanical property and microstructure at high temperature was studied.Microstructure of Fe-Al-Ta eutectic is composed of Fe_(2)Ta(Al)Laves phase and Fe(Al,Ta)matrix phase.In addition,the tensile strength at high temperatures is higher than that at room temperature.The tensile strength is increased with the increase of solidification rate.Moreover,fracture morphology transforms from cleavage fracture to dimple fracture as the solidification rate is increased at high temperatures.展开更多
Total nitrogen content,total nitrogen isotope(δ15 N),and free amino acid concentration in leaf of Phragmites australis(Cav.)Trin.ex Steud.under flooding for 0-11 d were studied.The results show that with the increase...Total nitrogen content,total nitrogen isotope(δ15 N),and free amino acid concentration in leaf of Phragmites australis(Cav.)Trin.ex Steud.under flooding for 0-11 d were studied.The results show that with the increase of flooding days,there is no significant variation in total nitrogen content in leaf of P.australis,δ15 N value shows a gradual tend to be negative,and concentrations of total free amino acids,Ser,Asp,and Asn first increase and then decrease.Under flooding for 1 d,δ15 N value decreases obviously and free amino acid concentration increases obviously compared with those under flooding for 0 d.It is indicated thatδ15 N value and free amino acid concentration are good indicators of P.australis under flooding condition.展开更多
基金Funded by National Natural Science Foundation of China(No.51201121)Key Industry Innovation Chain(group)Project of Shaanxi Province(No.2019ZDLGY 04-04)+1 种基金International Cooperation Project of Key R&D Program in Shaanxi Province(No.2020KW-033)Industrialization Project of Shaanxi Provincial Department of Education(No.20JC024)
文摘Fe-Al-Ta eutectic composites with solidification rates of 6,20,30,80 and 200μm/s were obtained by a modified Bridgman directional solidification technique and alloying.Moreover,tensile property and fracture behavior of Fe-Al-Ta eutectic composites were studied at 600℃.The relationship between mechanical property and microstructure at high temperature was studied.Microstructure of Fe-Al-Ta eutectic is composed of Fe_(2)Ta(Al)Laves phase and Fe(Al,Ta)matrix phase.In addition,the tensile strength at high temperatures is higher than that at room temperature.The tensile strength is increased with the increase of solidification rate.Moreover,fracture morphology transforms from cleavage fracture to dimple fracture as the solidification rate is increased at high temperatures.
文摘Total nitrogen content,total nitrogen isotope(δ15 N),and free amino acid concentration in leaf of Phragmites australis(Cav.)Trin.ex Steud.under flooding for 0-11 d were studied.The results show that with the increase of flooding days,there is no significant variation in total nitrogen content in leaf of P.australis,δ15 N value shows a gradual tend to be negative,and concentrations of total free amino acids,Ser,Asp,and Asn first increase and then decrease.Under flooding for 1 d,δ15 N value decreases obviously and free amino acid concentration increases obviously compared with those under flooding for 0 d.It is indicated thatδ15 N value and free amino acid concentration are good indicators of P.australis under flooding condition.
