In this work, an elegant method is proposed to derive the thermoelastic field in- duced by thermomechanical loadings in a decagonal quasicrystalline composite composed of an infinite matrix reinforced by an elliptical...In this work, an elegant method is proposed to derive the thermoelastic field in- duced by thermomechanical loadings in a decagonal quasicrystalline composite composed of an infinite matrix reinforced by an elliptical inclusion. The thermomechanical loadings include a uniform temperature change, remote uniform in-plane heat fluxes and remote uniform in-plane stresses. The corresponding boundary value problem is ultimately reduced to the solution of two independent sets of four coupled linear algebraic equations, each of which involves four complex constants characterizing the internal stress field. The solution demonstrates that a uniform tem- perature change and remote uniform stresses will induce an internal uniform stress field, and that uniform heat fluxes will result in a linearly distributed internal stress field within the elliptical inclusion. The induced uniform rigid body rotation within the inclusion is given explicitly.展开更多
This investigation presents the Green functions for a decagonal quasicrystalline ma- terial with a parabolic boundary subject to a line force and a line dislocation by means of the complex variable method. The surface...This investigation presents the Green functions for a decagonal quasicrystalline ma- terial with a parabolic boundary subject to a line force and a line dislocation by means of the complex variable method. The surface Green functions are treated as a special case, and the explicit expressions of displacements and hoop stress at the parabolic boundary are also given. Finally, the stresses and displacements induced by a phonon line force acting at the origin of the lower half-space are presented.展开更多
A pseudo-ternary alloy system was constructed by combining an icosahedralquasicrystal (IQC), a decagonal quasicrystal (DQC), and Zr into one alloy system. Differentproportions of Zr were added to pseudo-binary alloy I...A pseudo-ternary alloy system was constructed by combining an icosahedralquasicrystal (IQC), a decagonal quasicrystal (DQC), and Zr into one alloy system. Differentproportions of Zr were added to pseudo-binary alloy IQC_(80)DQC_(20) (mass fraction in %);Structural evolution in these alloys was discussed. An amorphous alloy composition was found in thissystem and a melt-spinning amorphous alloy was produced in this composition. Through DSC analysis,the amorphous alloy exhibits high glass forming ability comparable to that of the InoueZr_(65)Al_(7.5)Cu_(17.5)Ni_(10) amorphous alloy.展开更多
A decagonal quasicrystal, which is weakened by an arc-shaped crackpenetrating through the solid in the period direction, and which is subjected to remote uniformphonon stresses, is investigated by applying the complex...A decagonal quasicrystal, which is weakened by an arc-shaped crackpenetrating through the solid in the period direction, and which is subjected to remote uniformphonon stresses, is investigated by applying the complex variable method which is just developed bythe authors. It is found that the phonon and phason stresses near the crack tips exhibit inversesquare root singularities. The four complex stress functions characterizing the phonon and phasonfields are derived. Explicit expressions for the phonon and phason stress intensity factors, crackopening displacements and energy release rate are also presented.展开更多
在 A^1_(70)Cc_Ni(5)十次准晶中首次观察到三种类型层错,其中第一和第二类层错面垂直和平行于十次轴,其位移矢量 R 都在层错面内,且沿准周期方向。第三类层错是位移矢量不在层错面内的平移畴壁。用会聚束电子衍射方法首次测定了十次准...在 A^1_(70)Cc_Ni(5)十次准晶中首次观察到三种类型层错,其中第一和第二类层错面垂直和平行于十次轴,其位移矢量 R 都在层错面内,且沿准周期方向。第三类层错是位移矢量不在层错面内的平移畴壁。用会聚束电子衍射方法首次测定了十次准晶中位错的 Burgers矢 b 的模,观察到 b=[3/4,0,0,0,0,0],b=[1,0,0,0,0,0]的螺位错和 b=[1/2,0,0,0,0,0]的刃位错,且不少位错以同号平行位错对的形式存在。首次观察到十次准晶的三种小角晶界,即由刃位错壁构成的倾斜晶界,由螺位错壁构成的扭转晶界和由位错网络构成的小角晶界。最后探讨了十次准晶形变的微观机制。展开更多
基金supported by the National Natural Science Foundation of China(No.11272121)Innovation Program of Shanghai Municipal Education Commission,China(No.12ZZ058)the Natural Sciences and Engineering Research Council of Canada
文摘In this work, an elegant method is proposed to derive the thermoelastic field in- duced by thermomechanical loadings in a decagonal quasicrystalline composite composed of an infinite matrix reinforced by an elliptical inclusion. The thermomechanical loadings include a uniform temperature change, remote uniform in-plane heat fluxes and remote uniform in-plane stresses. The corresponding boundary value problem is ultimately reduced to the solution of two independent sets of four coupled linear algebraic equations, each of which involves four complex constants characterizing the internal stress field. The solution demonstrates that a uniform tem- perature change and remote uniform stresses will induce an internal uniform stress field, and that uniform heat fluxes will result in a linearly distributed internal stress field within the elliptical inclusion. The induced uniform rigid body rotation within the inclusion is given explicitly.
文摘This investigation presents the Green functions for a decagonal quasicrystalline ma- terial with a parabolic boundary subject to a line force and a line dislocation by means of the complex variable method. The surface Green functions are treated as a special case, and the explicit expressions of displacements and hoop stress at the parabolic boundary are also given. Finally, the stresses and displacements induced by a phonon line force acting at the origin of the lower half-space are presented.
基金This work wax financially supported by the French-Chinese Advanced Research Program on Materials (PRA MX 99/04) and by the National Natural Science Foundation of China (Nos. 59971014 and 50071013)
文摘A pseudo-ternary alloy system was constructed by combining an icosahedralquasicrystal (IQC), a decagonal quasicrystal (DQC), and Zr into one alloy system. Differentproportions of Zr were added to pseudo-binary alloy IQC_(80)DQC_(20) (mass fraction in %);Structural evolution in these alloys was discussed. An amorphous alloy composition was found in thissystem and a melt-spinning amorphous alloy was produced in this composition. Through DSC analysis,the amorphous alloy exhibits high glass forming ability comparable to that of the InoueZr_(65)Al_(7.5)Cu_(17.5)Ni_(10) amorphous alloy.
基金Project supported by the National Excellent Young Scholar Science Fund of China(No.10125209)the Teaching and Research Award Fuud for Outstanding Young Teachers in High Education Institutions of the Ministry of Education of China
文摘A decagonal quasicrystal, which is weakened by an arc-shaped crackpenetrating through the solid in the period direction, and which is subjected to remote uniformphonon stresses, is investigated by applying the complex variable method which is just developed bythe authors. It is found that the phonon and phason stresses near the crack tips exhibit inversesquare root singularities. The four complex stress functions characterizing the phonon and phasonfields are derived. Explicit expressions for the phonon and phason stress intensity factors, crackopening displacements and energy release rate are also presented.
文摘在 A^1_(70)Cc_Ni(5)十次准晶中首次观察到三种类型层错,其中第一和第二类层错面垂直和平行于十次轴,其位移矢量 R 都在层错面内,且沿准周期方向。第三类层错是位移矢量不在层错面内的平移畴壁。用会聚束电子衍射方法首次测定了十次准晶中位错的 Burgers矢 b 的模,观察到 b=[3/4,0,0,0,0,0],b=[1,0,0,0,0,0]的螺位错和 b=[1/2,0,0,0,0,0]的刃位错,且不少位错以同号平行位错对的形式存在。首次观察到十次准晶的三种小角晶界,即由刃位错壁构成的倾斜晶界,由螺位错壁构成的扭转晶界和由位错网络构成的小角晶界。最后探讨了十次准晶形变的微观机制。
