Microscopic phase-field method was used to simulate the site occupation of a series of alloys with a stoichiometric composition of Ni75Al25?xFex (x=0, 5?10) aged at 1273 K. With the change of Fe content, quantitative ...Microscopic phase-field method was used to simulate the site occupation of a series of alloys with a stoichiometric composition of Ni75Al25?xFex (x=0, 5?10) aged at 1273 K. With the change of Fe content, quantitative calculations were made on each atomic site occupation probability (SOP) in L12-Ni3 (Al1?xFex), so as to find out the dynamic response law. The result of the study shows that, with the increase of Fe content, the Fe atom preferentially occupies the B sites (corner sites of FCC) with its SOP value being increased gradually, and the SOP of the Al atom on the B sites is greatly decreased. Meanwhile, AlNi and FeNi anti-sites form in the precipitation of L12 phase. Moreover, with the increase of Fe content, the formation of AlNi and FeNi anti-sites becomes much easier. In addition, it has been found that the instantaneous dynamic evolution of the atomic SOP is completed at the early stage of the growth of L12 phases.展开更多
Exploration of new material systems and optical performance enhancement are huge challenges for the study of infrared nonlinear optical(IR NLO)materials.In this work,the first thioborate-thiogermanate and thioborate-t...Exploration of new material systems and optical performance enhancement are huge challenges for the study of infrared nonlinear optical(IR NLO)materials.In this work,the first thioborate-thiogermanate and thioborate-thiostannate compounds,Ca_(2)La(Ge_(0.72)Si_(0.28)S_(4))(BS_(3))and Ca_(2)La(Sn_(0.75)Si_(0.25)S_(4))(BS_(3)),containing both co-occupied Ca^(2+)/La^(3+)cation and[Ge/SiS_(4)]^(4-)or[Sn/SiS_(4)]^(4-)anion sites,respectively,were designed through an atomic site co-occupancy strategy.They inherited favourable 3D network structures in which the effectively aligned[MS_(4)]^(4-)and[BS_(3)]^(3-)functional anions were bridged by Ca^(2+)/La^(3+)cations.Remarkably,the title compounds achieved excellent IR NLO properties,including good chemical and thermal stabilities,wide light transmission ranges(0.45-11μm),strong second harmonic generation responses(1.5 and 2.0 times that of commercial AgGaS2 at 2.05μm)and high laser-induced damage thresholds(7 and 6 times that of AgGaS2).Theoretical calculation and experimental results revealed that,on the basis of excellent structural framework,introducing more active functional groups through atomic site co-occupancy could simultaneously enhance the second harmonic generation effect and maintain a relatively high laser-induced damage threshold.This work not only offers an easier synthetic route for mixed anionic thioborates but also provides inspiration for the design of well-performed NLO materials.展开更多
基金Project(2013011014-1)supported by the Natural Science Funds of Shanxi Province,ChinaProject(2009021028)supported by Science and Technique Foundation for Young Scholars of Shanxi Province,China
文摘Microscopic phase-field method was used to simulate the site occupation of a series of alloys with a stoichiometric composition of Ni75Al25?xFex (x=0, 5?10) aged at 1273 K. With the change of Fe content, quantitative calculations were made on each atomic site occupation probability (SOP) in L12-Ni3 (Al1?xFex), so as to find out the dynamic response law. The result of the study shows that, with the increase of Fe content, the Fe atom preferentially occupies the B sites (corner sites of FCC) with its SOP value being increased gradually, and the SOP of the Al atom on the B sites is greatly decreased. Meanwhile, AlNi and FeNi anti-sites form in the precipitation of L12 phase. Moreover, with the increase of Fe content, the formation of AlNi and FeNi anti-sites becomes much easier. In addition, it has been found that the instantaneous dynamic evolution of the atomic SOP is completed at the early stage of the growth of L12 phases.
基金supported by the National Natural Science Foundation of China(No.22031009,22375201,and 21921001)the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(CXZX-2022-GH06).
文摘Exploration of new material systems and optical performance enhancement are huge challenges for the study of infrared nonlinear optical(IR NLO)materials.In this work,the first thioborate-thiogermanate and thioborate-thiostannate compounds,Ca_(2)La(Ge_(0.72)Si_(0.28)S_(4))(BS_(3))and Ca_(2)La(Sn_(0.75)Si_(0.25)S_(4))(BS_(3)),containing both co-occupied Ca^(2+)/La^(3+)cation and[Ge/SiS_(4)]^(4-)or[Sn/SiS_(4)]^(4-)anion sites,respectively,were designed through an atomic site co-occupancy strategy.They inherited favourable 3D network structures in which the effectively aligned[MS_(4)]^(4-)and[BS_(3)]^(3-)functional anions were bridged by Ca^(2+)/La^(3+)cations.Remarkably,the title compounds achieved excellent IR NLO properties,including good chemical and thermal stabilities,wide light transmission ranges(0.45-11μm),strong second harmonic generation responses(1.5 and 2.0 times that of commercial AgGaS2 at 2.05μm)and high laser-induced damage thresholds(7 and 6 times that of AgGaS2).Theoretical calculation and experimental results revealed that,on the basis of excellent structural framework,introducing more active functional groups through atomic site co-occupancy could simultaneously enhance the second harmonic generation effect and maintain a relatively high laser-induced damage threshold.This work not only offers an easier synthetic route for mixed anionic thioborates but also provides inspiration for the design of well-performed NLO materials.
