China should actively guide the yuan’s exchange rate to about 6.93 against the dollar to help maintain economic growth and bolster employment,according to a report by the Ministry of Finance’s research institute.
A positive correlation between strength and elastic modulus is generally observed in metallic alloys,where the addition of a stronger element such as Mo,W,or Cr increases both the strength and elastic modulus.Our dens...A positive correlation between strength and elastic modulus is generally observed in metallic alloys,where the addition of a stronger element such as Mo,W,or Cr increases both the strength and elastic modulus.Our density functional theory(DFT)calculations explain an opposite experimentally measured trend,i.e.,the addition of a weaker element such as Ti,Hf,or Zr enhances the yield strength in specific high entropy alloys(HEAs).We show that the underlying mechanism is the lower bond stiffness of the weaker element,which causes larger local lattice distortion(LLD).Higher lattice distortion pins themovement of dislocations,causing solid solution strengthening,thereby raising the strength in body-centered cubic(BCC)refractory HEAs.We show this unintuitive behavior in Ti-based HEAs,i.e.,TixMoNbTaW,and compare it with the conventional behavior in Mo_(x)NbTiV_(0.3)Zr.展开更多
文摘China should actively guide the yuan’s exchange rate to about 6.93 against the dollar to help maintain economic growth and bolster employment,according to a report by the Ministry of Finance’s research institute.
基金supported by the US Department of Energy,Office of Science,Basic Energy Science,Mechanical Behavior and Radiation Effects program.
文摘A positive correlation between strength and elastic modulus is generally observed in metallic alloys,where the addition of a stronger element such as Mo,W,or Cr increases both the strength and elastic modulus.Our density functional theory(DFT)calculations explain an opposite experimentally measured trend,i.e.,the addition of a weaker element such as Ti,Hf,or Zr enhances the yield strength in specific high entropy alloys(HEAs).We show that the underlying mechanism is the lower bond stiffness of the weaker element,which causes larger local lattice distortion(LLD).Higher lattice distortion pins themovement of dislocations,causing solid solution strengthening,thereby raising the strength in body-centered cubic(BCC)refractory HEAs.We show this unintuitive behavior in Ti-based HEAs,i.e.,TixMoNbTaW,and compare it with the conventional behavior in Mo_(x)NbTiV_(0.3)Zr.
