Rejuvenation is the structural excitation of glassy materials,and is a promising approach for improving the macroscopic deformability of metallic glasses.This atomistic study proposes the application of compressive hy...Rejuvenation is the structural excitation of glassy materials,and is a promising approach for improving the macroscopic deformability of metallic glasses.This atomistic study proposes the application of compressive hydrostatic pressure during the glass-forming quenching process and demonstrates highly rejuvenated glass states that have not been attainable without the application of pressure.Surprisingly,the pressure-promoted rejuvenation process increases the characteristic short-and mediumrange order,even though it leads to a higher-energy glassy state.This‘local order’–‘energy’relation is completely opposite to conventional thinking regarding the relation,suggesting the presence of a well-ordered high-pressure glass/high-energy glass phase.We also demonstrate that the rejuvenated glass made by the pressure-promoted rejuvenation exhibits greater plastic performance than as-quenched glass,and greater strength and stiffness than glass made without the application of pressure.It is thus possible to tune the mechanical properties of glass using the pressure-promoted rejuvenation technique.展开更多
A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed.The method takes fluctuations of force constants due to magnet...A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed.The method takes fluctuations of force constants due to magnetic excitations as well as due to chemical disorder into account.The developed approach correctly predicts the experimentally observed unusual phonon hardening of a transverse acoustic mode in Fe–Pd an Fe–Pt Invar alloys with increasing temperature.This peculiar behavior,which cannot be explained within a conventional harmonic picture,turns out to be a consequence of thermal magnetic fluctuations.The proposed methodology can be straightforwardly applied to a wide range of materials to reveal new insights into physical behaviors and to design materials through computation,which were not accessible so far.展开更多
基金supported by the following funding awards:Grants-in-Aid for Scientific Research in Innovative Area(no.22102003)Scientific Research(A)(no.23246025)+1 种基金Challenging Exploratory Research(no.25630013)the Elements Strategy Initiative for Structural Materials(ESISM).
文摘Rejuvenation is the structural excitation of glassy materials,and is a promising approach for improving the macroscopic deformability of metallic glasses.This atomistic study proposes the application of compressive hydrostatic pressure during the glass-forming quenching process and demonstrates highly rejuvenated glass states that have not been attainable without the application of pressure.Surprisingly,the pressure-promoted rejuvenation process increases the characteristic short-and mediumrange order,even though it leads to a higher-energy glassy state.This‘local order’–‘energy’relation is completely opposite to conventional thinking regarding the relation,suggesting the presence of a well-ordered high-pressure glass/high-energy glass phase.We also demonstrate that the rejuvenated glass made by the pressure-promoted rejuvenation exhibits greater plastic performance than as-quenched glass,and greater strength and stiffness than glass made without the application of pressure.It is thus possible to tune the mechanical properties of glass using the pressure-promoted rejuvenation technique.
基金Funding by the Ministry of Education,Culture,Sports,Science,and Technology(MEXT)Japan,through Elements Strategy Initiative for Structural Materials(ESISM)of Kyoto University+4 种基金by the Japan Society for the Promotion of Science(JSPS)KAKENHI Grant-in-Aid for Young Scientist(B)(Grant No.16K18228)by the European Research Council under the EU’s 7th Framework Programme(FP7/2007-2013)/ERC Grant agreement 290998the Grant-in-Aid for Scientific Research on Innovative Areas Nano Informatics(Grant No.25106005)from the Japan Society for the Promotion of Science(JSPS)by the Deutsche Forschungsgemeinschaft(DFG)for the scholarship KO 5080/1-1by the DFG for their funding within the priority programme SPP 1599.
文摘A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed.The method takes fluctuations of force constants due to magnetic excitations as well as due to chemical disorder into account.The developed approach correctly predicts the experimentally observed unusual phonon hardening of a transverse acoustic mode in Fe–Pd an Fe–Pt Invar alloys with increasing temperature.This peculiar behavior,which cannot be explained within a conventional harmonic picture,turns out to be a consequence of thermal magnetic fluctuations.The proposed methodology can be straightforwardly applied to a wide range of materials to reveal new insights into physical behaviors and to design materials through computation,which were not accessible so far.
