A method based on electronic structure calculation is proposed to predict the substitution behavior of elements in ordered intermetallics. The electronic structure of 20 alloying elements in TiAl is calculated using ...A method based on electronic structure calculation is proposed to predict the substitution behavior of elements in ordered intermetallics. The electronic structure of 20 alloying elements in TiAl is calculated using the DV-Xα cluster method The bond orders between alloying elements and surrounding atoms, Bo_Ti,Bo_Al, are used as parameters. Two lines on the Bo_Ti-Bo_Al diagram separate the elements into three groups. The elements located outside of the two lines substitute either Ti or Al atom regardless of the composition of TiAl. The substitution behavior of elements between the two lines will be affected by the Ti/Al ratio and the amount of alloying elements added Substituting sequence in multi-element alloy is discussed The prediction based on this method agrees well with the experimental results.展开更多
The morphology and crystallographic orientation of(α_2+γ)lamellar structure in duplex Ti-47.5Al-2.5V intermetallic compound have been studied by means of TEM, microdiffraction as well as 180° and non-180° ...The morphology and crystallographic orientation of(α_2+γ)lamellar structure in duplex Ti-47.5Al-2.5V intermetallic compound have been studied by means of TEM, microdiffraction as well as 180° and non-180° rotation twinning analysis.A possible atomic model of the interface was suggested.Thus,approach was made to a mechanism on complex nucleation of α_2+γ two phases along α-Ti interface,and growth of α_2/γ/γ_1/α_2 or α_2/γ/α_2/γ as fundamental structural unit.展开更多
The rapidly solidified powder of Ti-34Al-2Mn alloy was obtained by means of ultrasonic gas atomisation (USGA) technique.The tupical size of the powder is 27 μm.X-ray diffraction results show that the powder consists ...The rapidly solidified powder of Ti-34Al-2Mn alloy was obtained by means of ultrasonic gas atomisation (USGA) technique.The tupical size of the powder is 27 μm.X-ray diffraction results show that the powder consists of major α_2-phase and minor γ-phase.Under optical microscope both equiaxed and dendritical microstructure features were observed on RS pow- der sections.After annealing at 900 ℃/for 2 h in vacuum,most of α_2-phase transforms into γ-phase,resulting in refinement of structure.展开更多
文摘A method based on electronic structure calculation is proposed to predict the substitution behavior of elements in ordered intermetallics. The electronic structure of 20 alloying elements in TiAl is calculated using the DV-Xα cluster method The bond orders between alloying elements and surrounding atoms, Bo_Ti,Bo_Al, are used as parameters. Two lines on the Bo_Ti-Bo_Al diagram separate the elements into three groups. The elements located outside of the two lines substitute either Ti or Al atom regardless of the composition of TiAl. The substitution behavior of elements between the two lines will be affected by the Ti/Al ratio and the amount of alloying elements added Substituting sequence in multi-element alloy is discussed The prediction based on this method agrees well with the experimental results.
文摘The morphology and crystallographic orientation of(α_2+γ)lamellar structure in duplex Ti-47.5Al-2.5V intermetallic compound have been studied by means of TEM, microdiffraction as well as 180° and non-180° rotation twinning analysis.A possible atomic model of the interface was suggested.Thus,approach was made to a mechanism on complex nucleation of α_2+γ two phases along α-Ti interface,and growth of α_2/γ/γ_1/α_2 or α_2/γ/α_2/γ as fundamental structural unit.
文摘The rapidly solidified powder of Ti-34Al-2Mn alloy was obtained by means of ultrasonic gas atomisation (USGA) technique.The tupical size of the powder is 27 μm.X-ray diffraction results show that the powder consists of major α_2-phase and minor γ-phase.Under optical microscope both equiaxed and dendritical microstructure features were observed on RS pow- der sections.After annealing at 900 ℃/for 2 h in vacuum,most of α_2-phase transforms into γ-phase,resulting in refinement of structure.
