The microstructural features,shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by dierential scanning calorimetry(DSC),scanning electron microscopy(SEM),transmission electron micr...The microstructural features,shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by dierential scanning calorimetry(DSC),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and thermal cycling test under various stresses.The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system.The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temperatures. However,it was found that in NiMn40Fe10 alloy the martensitic transformation is not thermoelastic in nature. The mechanism of this transformation and the crystallography of Ni-Mn(50-x)-Fex(x=5,7,10,20 at.pct) alloys are presented.展开更多
Using Monte Carlo simulations,we study the universal classes of criticality associated to the superlattices CddMn1-d Te/CdTe and the spinels ZndCd1-dCr2S[Se]4.Both systems are diluted frustrated antiferromagnets.The r...Using Monte Carlo simulations,we study the universal classes of criticality associated to the superlattices CddMn1-d Te/CdTe and the spinels ZndCd1-dCr2S[Se]4.Both systems are diluted frustrated antiferromagnets.The ratio d of dilution or substitution is found to greatly influence the nature of criticality.The effect of dimensionality in spin glass transitions is also investigated.展开更多
Phase transition and band structure tuned by uniaxial and biaxial strains are systematically investigated based on the density-functional theory for ordered Al_(1/2)Ga_(1/2)N alloys of complex structures.Although the ...Phase transition and band structure tuned by uniaxial and biaxial strains are systematically investigated based on the density-functional theory for ordered Al_(1/2)Ga_(1/2)N alloys of complex structures.Although the structural transformations to graphite-like from wurtzite are energetically favorable for both types of strain,the phase transitions are different in nature:the second-order transition induced by uniaxial strain is jointly driven by the mechanical and dynamical instabilities and the first-order transition by biaxial strain only by the mechanical instability.The wurtzite phase always shows the direct band gap,while the band gap of the graphite-like phase is always indirect.Furthermore,the band gaps of the wurtzite phase can be reduced by both types of strain,while that of the graphite-like phase is enhanced by uniaxial strain and is suppressed by biaxial strain.展开更多
基金express their gratitude to the Ministry of Education,Culture and Sports of Japan(MEXT) for partially supporting this research
文摘The microstructural features,shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by dierential scanning calorimetry(DSC),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and thermal cycling test under various stresses.The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system.The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temperatures. However,it was found that in NiMn40Fe10 alloy the martensitic transformation is not thermoelastic in nature. The mechanism of this transformation and the crystallography of Ni-Mn(50-x)-Fex(x=5,7,10,20 at.pct) alloys are presented.
文摘Using Monte Carlo simulations,we study the universal classes of criticality associated to the superlattices CddMn1-d Te/CdTe and the spinels ZndCd1-dCr2S[Se]4.Both systems are diluted frustrated antiferromagnets.The ratio d of dilution or substitution is found to greatly influence the nature of criticality.The effect of dimensionality in spin glass transitions is also investigated.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No 2013QNA38
文摘Phase transition and band structure tuned by uniaxial and biaxial strains are systematically investigated based on the density-functional theory for ordered Al_(1/2)Ga_(1/2)N alloys of complex structures.Although the structural transformations to graphite-like from wurtzite are energetically favorable for both types of strain,the phase transitions are different in nature:the second-order transition induced by uniaxial strain is jointly driven by the mechanical and dynamical instabilities and the first-order transition by biaxial strain only by the mechanical instability.The wurtzite phase always shows the direct band gap,while the band gap of the graphite-like phase is always indirect.Furthermore,the band gaps of the wurtzite phase can be reduced by both types of strain,while that of the graphite-like phase is enhanced by uniaxial strain and is suppressed by biaxial strain.
