Information of defects and 3d electrons in transition metals (Ti,V,Cu) and TiAl-based alloys (Ti50Al50,Ti50Al48V2,Ti50Al48Cu2) can be extracted from the positron lifetime and coincidence Doppler broadening spectra. Th...Information of defects and 3d electrons in transition metals (Ti,V,Cu) and TiAl-based alloys (Ti50Al50,Ti50Al48V2,Ti50Al48Cu2) can be extracted from the positron lifetime and coincidence Doppler broadening spectra. The results show that the 3d electron signals for the transition metals Ti,V and Cu increase with the number of 3d electrons. The 3d electron signal and the electron density for binary TiAl alloy are relatively low due to the (Ti)3d-(Al)3p interactions. The addition of V and Cu atoms to TiAl alloy leads to the increase in the electron densities in bulk and the defects on grain boundaries simultaneously,as well as the enhancement of the 3d electron signal. The 3d electron signal in the spectrum of Ti50Al48Cu2 alloy is higher than that of Ti50Al48V2 alloy.展开更多
Hydrogen damage in iron or 99.99% purity has been investigated by Doppler broadening measurement.Experimental results show that when the iron is charged with hydrogen in 0.5mol/L H_2SO_4 solution,the critical current ...Hydrogen damage in iron or 99.99% purity has been investigated by Doppler broadening measurement.Experimental results show that when the iron is charged with hydrogen in 0.5mol/L H_2SO_4 solution,the critical current density to cause hydrogen damage is 20mA/cm^2.While a little As_2O_3,saying 250mg/L,added to H_2SO_4 solution,even rather small current density.≤0.2mA/cm^2,would cause hydrogen damage.With the help ofi slow tensile test,it revealed that the hydrogen damage occurred in the specimen may be influential to the subsequent process of deformation and fracture.展开更多
基金the National Natural Science Foundation of China (Grant No 50361002)Guangxi University Key Program for Science and Technology Research (Grant No 2003ZD04)the Natural Science Foundation of Guangxi Province (Grant No 0480004)
文摘Information of defects and 3d electrons in transition metals (Ti,V,Cu) and TiAl-based alloys (Ti50Al50,Ti50Al48V2,Ti50Al48Cu2) can be extracted from the positron lifetime and coincidence Doppler broadening spectra. The results show that the 3d electron signals for the transition metals Ti,V and Cu increase with the number of 3d electrons. The 3d electron signal and the electron density for binary TiAl alloy are relatively low due to the (Ti)3d-(Al)3p interactions. The addition of V and Cu atoms to TiAl alloy leads to the increase in the electron densities in bulk and the defects on grain boundaries simultaneously,as well as the enhancement of the 3d electron signal. The 3d electron signal in the spectrum of Ti50Al48Cu2 alloy is higher than that of Ti50Al48V2 alloy.
文摘Hydrogen damage in iron or 99.99% purity has been investigated by Doppler broadening measurement.Experimental results show that when the iron is charged with hydrogen in 0.5mol/L H_2SO_4 solution,the critical current density to cause hydrogen damage is 20mA/cm^2.While a little As_2O_3,saying 250mg/L,added to H_2SO_4 solution,even rather small current density.≤0.2mA/cm^2,would cause hydrogen damage.With the help ofi slow tensile test,it revealed that the hydrogen damage occurred in the specimen may be influential to the subsequent process of deformation and fracture.
