The effect of prior deformation on the mechanical properties and microstructural evolution of aging process in a Cu-30Ni-25Fe (in at. pct) alloy has been studied by tensile test, hardness measurement, SEM and optical ...The effect of prior deformation on the mechanical properties and microstructural evolution of aging process in a Cu-30Ni-25Fe (in at. pct) alloy has been studied by tensile test, hardness measurement, SEM and optical microscopy analysis. The results show that spinodal decomposition and recovery process interact on each other when aged at low temperature (600 degrees C), and most of the defects induced by cold-work did not disappear in 100 h. When aged at high temperature (850 degrees C), the discontinuous coarsening of the spinodal products takes place. The increase in yield strength and elongation of the sample aged at 850 degrees C for 5 h after deformation mainly results from the submicrometer grains produced by discontinous coarsening of spinodal products.展开更多
The alpha(alpha(2))/gamma phase equilibria in Ti-Al-X(X=C,B,Fe,Si in at, pct) ternary systems were studied by equilibrium heat-treatment and EPMA. The results show that the addition of B to the Ti-Al binary system lea...The alpha(alpha(2))/gamma phase equilibria in Ti-Al-X(X=C,B,Fe,Si in at, pct) ternary systems were studied by equilibrium heat-treatment and EPMA. The results show that the addition of B to the Ti-Al binary system leads to a shift of both alpha(alpha(2))/[alpha(alpha(2))+gamma] and [(alpha(alpha(2))+gamma]/gamma phase boundaries to Al-rich side and 0.1 B addition decreases T-alpha by 18 degrees C. The addition of C leads to a shift of [alpha(alpha(2))+gamma]/gamma phase boundary to Al-rich side but the effect of 0.2 at, pet C addition on T-alpha is very slight. The addition of Fe results in alpha(alpha(2))/[alpha(alpha(2))+gamma] and [alpha(alpha(2))+gamma]/gamma phase boundaries shifting to Ti-rich side and 1.0 Fe addition increases T-alpha by 90 similar to 110 degrees C. The addition of Si leads to a shift of alpha(alpha(2))/[alpha(alpha(2))/[alpha(alpha(2))+gamma] phase boundary to Ti-rich side and the 0.3 Si addition increases T-alpha by 80 similar to 110 degrees C. The solubilities for C, B and Si in alpha(alpha(2)) phase are higher than those in the gamma phase but the solubility for Fe in alpha(alpha(2)) phase is lower than that in gamma phase.展开更多
By using the geometric analysis of grand potential, the molar grand potential-effective chemical potential curve of solution with magnetic transition can be obtained from the relevant molar free energy diagram, and it...By using the geometric analysis of grand potential, the molar grand potential-effective chemical potential curve of solution with magnetic transition can be obtained from the relevant molar free energy diagram, and it is shown that the grand potential and effective chemical potential can be separated into paramagnetic and magnetic terms. In addition, the CVM has been combined with the present magnetic transition free energy model such as M. Hillert and T. Nishizawa's models to calculate phase equilibria between solutions with magnetic transition, and this combined method has been applied to the alpha/gamma phase equilibrium in the Fe-Mn binary system and found to be feasible.展开更多
Microstructures and room-temperature tensile properties of isothermally-forged gamma-base (gamma + alpha(2)) alloys in Ti-AI-Nb-Cr-V system with different heat treatments were investigated. The results show that the m...Microstructures and room-temperature tensile properties of isothermally-forged gamma-base (gamma + alpha(2)) alloys in Ti-AI-Nb-Cr-V system with different heat treatments were investigated. The results show that the microstructures of Ti-47Al-2Nb-1Cr-1V and Ti-47Al-2V-1Cr (at. pet) alloys are mainly determined by heat treating temperature in the (alpha + gamma) two-phase field, and the joint additions of Nb, Ci and V in the Ti-47Al alloy affect T-alpha significantly. The microstructure of Ti-47Al alloy with additions of Nb, Cr and V (1 similar to 2 at. pat) can be duplex or nearly-lamellar by a suitable heat treatment after isothermal forging at 1000 degrees C for over 50% plastic strains. Therefore its tensile properties can be improved at room temperature.展开更多
文摘The effect of prior deformation on the mechanical properties and microstructural evolution of aging process in a Cu-30Ni-25Fe (in at. pct) alloy has been studied by tensile test, hardness measurement, SEM and optical microscopy analysis. The results show that spinodal decomposition and recovery process interact on each other when aged at low temperature (600 degrees C), and most of the defects induced by cold-work did not disappear in 100 h. When aged at high temperature (850 degrees C), the discontinuous coarsening of the spinodal products takes place. The increase in yield strength and elongation of the sample aged at 850 degrees C for 5 h after deformation mainly results from the submicrometer grains produced by discontinous coarsening of spinodal products.
文摘The alpha(alpha(2))/gamma phase equilibria in Ti-Al-X(X=C,B,Fe,Si in at, pct) ternary systems were studied by equilibrium heat-treatment and EPMA. The results show that the addition of B to the Ti-Al binary system leads to a shift of both alpha(alpha(2))/[alpha(alpha(2))+gamma] and [(alpha(alpha(2))+gamma]/gamma phase boundaries to Al-rich side and 0.1 B addition decreases T-alpha by 18 degrees C. The addition of C leads to a shift of [alpha(alpha(2))+gamma]/gamma phase boundary to Al-rich side but the effect of 0.2 at, pet C addition on T-alpha is very slight. The addition of Fe results in alpha(alpha(2))/[alpha(alpha(2))+gamma] and [alpha(alpha(2))+gamma]/gamma phase boundaries shifting to Ti-rich side and 1.0 Fe addition increases T-alpha by 90 similar to 110 degrees C. The addition of Si leads to a shift of alpha(alpha(2))/[alpha(alpha(2))/[alpha(alpha(2))+gamma] phase boundary to Ti-rich side and the 0.3 Si addition increases T-alpha by 80 similar to 110 degrees C. The solubilities for C, B and Si in alpha(alpha(2)) phase are higher than those in the gamma phase but the solubility for Fe in alpha(alpha(2)) phase is lower than that in gamma phase.
文摘By using the geometric analysis of grand potential, the molar grand potential-effective chemical potential curve of solution with magnetic transition can be obtained from the relevant molar free energy diagram, and it is shown that the grand potential and effective chemical potential can be separated into paramagnetic and magnetic terms. In addition, the CVM has been combined with the present magnetic transition free energy model such as M. Hillert and T. Nishizawa's models to calculate phase equilibria between solutions with magnetic transition, and this combined method has been applied to the alpha/gamma phase equilibrium in the Fe-Mn binary system and found to be feasible.
文摘Microstructures and room-temperature tensile properties of isothermally-forged gamma-base (gamma + alpha(2)) alloys in Ti-AI-Nb-Cr-V system with different heat treatments were investigated. The results show that the microstructures of Ti-47Al-2Nb-1Cr-1V and Ti-47Al-2V-1Cr (at. pet) alloys are mainly determined by heat treating temperature in the (alpha + gamma) two-phase field, and the joint additions of Nb, Ci and V in the Ti-47Al alloy affect T-alpha significantly. The microstructure of Ti-47Al alloy with additions of Nb, Cr and V (1 similar to 2 at. pat) can be duplex or nearly-lamellar by a suitable heat treatment after isothermal forging at 1000 degrees C for over 50% plastic strains. Therefore its tensile properties can be improved at room temperature.
