In order to understand the effect of Mo alloying on the microstructural evolution of TiAl alloy, the as-cast microstructure, heat treated microstructure characteristic, and hot compression microstructure evolution of ...In order to understand the effect of Mo alloying on the microstructural evolution of TiAl alloy, the as-cast microstructure, heat treated microstructure characteristic, and hot compression microstructure evolution of Ti-44Al alloy have been studied in this work. The as-cast microstructure morphology changes from （γ＋α2） lamellar colony and β/β0＋γ mixture structure to β/β0 phase matrix widmannstatten structure, when Mo content increases from 2 at.% to 6 at.%. Affected by the relationship between β phase and α90℃phase, the angles between the lamellar orientation and the block β/β0 phase are roughly at 0℃, 45℃ and 90℃. Comparing with heat treatment microstructure, the hot compression microstructure contains less β/β0 phase, however, theβ/β0 phase containing 2Mo alloy and 3Mo alloy hot compressed at 1275 ℃ has the inverse tendency. In addition, （α2 ＋γ） colony is decomposed by the discontinuous transformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.展开更多
The present paper develops an analytical model for multi-electrodes in multi-layered piezoelectric actuators, in which the electrodes are vertical to and terminated at the edges of the medium and electroelastic field ...The present paper develops an analytical model for multi-electrodes in multi-layered piezoelectric actuators, in which the electrodes are vertical to and terminated at the edges of the medium and electroelastic field concentrations ahead of the electrodes in the multilayer piezoelectric actuators are examined. By considering a representative unit in realistic multilayers, the problem is formulated in terms of electric potential between the electrode tips and results in a system of singular integral equations in which the electric potential is taken as unknown function. Effects are investigated of electrode spacing and piezoelectric coupling on the singular electroelastic fields at the electrode tips, and closed-form expressions are given for the electromechanical field near the electrode tips. Exact solution for un-coupled dielectrics is provided, where no piezoelectric coupling is present.展开更多
基金supported financially by the National Natural Science Foundation of China (Nos. 51604191, 51504163 and5 1501100)the Natural Science Foundation for Young Scientists of Shanxi Province, China (No. 201701D221075)+2 种基金the State Key Laboratory for Advanced Metal and Materials foundation (No. 2014-ZD06)the Special/Youth Foundation of Taiyuan University of Technology (Nos. 2015QN014, 2013T004 and 2013T003)the financial support of the Qualified Personnel Foundation of Taiyuan University of Technology (Nos. tyutrc201342a and tyutrc201343a)
文摘In order to understand the effect of Mo alloying on the microstructural evolution of TiAl alloy, the as-cast microstructure, heat treated microstructure characteristic, and hot compression microstructure evolution of Ti-44Al alloy have been studied in this work. The as-cast microstructure morphology changes from （γ＋α2） lamellar colony and β/β0＋γ mixture structure to β/β0 phase matrix widmannstatten structure, when Mo content increases from 2 at.% to 6 at.%. Affected by the relationship between β phase and α90℃phase, the angles between the lamellar orientation and the block β/β0 phase are roughly at 0℃, 45℃ and 90℃. Comparing with heat treatment microstructure, the hot compression microstructure contains less β/β0 phase, however, theβ/β0 phase containing 2Mo alloy and 3Mo alloy hot compressed at 1275 ℃ has the inverse tendency. In addition, （α2 ＋γ） colony is decomposed by the discontinuous transformation.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.
文摘The present paper develops an analytical model for multi-electrodes in multi-layered piezoelectric actuators, in which the electrodes are vertical to and terminated at the edges of the medium and electroelastic field concentrations ahead of the electrodes in the multilayer piezoelectric actuators are examined. By considering a representative unit in realistic multilayers, the problem is formulated in terms of electric potential between the electrode tips and results in a system of singular integral equations in which the electric potential is taken as unknown function. Effects are investigated of electrode spacing and piezoelectric coupling on the singular electroelastic fields at the electrode tips, and closed-form expressions are given for the electromechanical field near the electrode tips. Exact solution for un-coupled dielectrics is provided, where no piezoelectric coupling is present.
