The aged and quenched microstructures of both alloys, Ti-42at-%Al and Ti-45at -%Al,homogenized in the disordered single phase field. were investigated And the results show that the quinched microstructure is a supersa...The aged and quenched microstructures of both alloys, Ti-42at-%Al and Ti-45at -%Al,homogenized in the disordered single phase field. were investigated And the results show that the quinched microstructure is a supersaturated single phase of ordered 22. When the supersaturated phase is aged in the two phase range at 1273 and 1373 K, it will transform to a lamellar microstructure of γ+α2. with a discontinuous decomposition mechanism in Ti-42at-%Al alloy and a semicontinuous decomposition mechanism in T1-45at-%Al alloy. With the methods of quantitative metallograph examination and X-ray diffraction analysis. the relationship between the amount of γ, phase precipitation and the time of isothermal transformation is agreed展开更多
The relationship between structure and hysteresis of phase transformation temperature in NiTi shape memory alloy has been investigated by means of TEM observation,positron an- nihilation and electrical resistivity mea...The relationship between structure and hysteresis of phase transformation temperature in NiTi shape memory alloy has been investigated by means of TEM observation,positron an- nihilation and electrical resistivity measurement.The sequence of hysteresis for the alloy aged under different regimes was found to be:plate martensite>R-phase>tie-like martensite. The reversible displaeement of phase boundaries of these transformations is blocked by the co- herent stress field around Ti_(11)Ni_(14)phase particles.A linear relationship between S paramet- er of positron annihilation and maximum values of temperature hysteresis showed that the mismatch dislocation and elastic stress field established by Ti_(11)Ni_(14)phase precipitation are the main factor to determine the temperature hysteresis of phase transformation in NiTi shape memory alloy.展开更多
The microstructure and the stability of Fe_73.5Cu_1Nb_3Si_13.5B_9 alloy at different stages of phase transformation were investigated through the observation of X-ray difraction and transmission electron microscopy an...The microstructure and the stability of Fe_73.5Cu_1Nb_3Si_13.5B_9 alloy at different stages of phase transformation were investigated through the observation of X-ray difraction and transmission electron microscopy and the measurement of magnetic aftereffect (MAE). It was found that the dependence of the volume fraction of amorphous phase and the MAE in the samples annealed from 450 to 700℃ on the annealing temperature is similar.展开更多
文摘The aged and quenched microstructures of both alloys, Ti-42at-%Al and Ti-45at -%Al,homogenized in the disordered single phase field. were investigated And the results show that the quinched microstructure is a supersaturated single phase of ordered 22. When the supersaturated phase is aged in the two phase range at 1273 and 1373 K, it will transform to a lamellar microstructure of γ+α2. with a discontinuous decomposition mechanism in Ti-42at-%Al alloy and a semicontinuous decomposition mechanism in T1-45at-%Al alloy. With the methods of quantitative metallograph examination and X-ray diffraction analysis. the relationship between the amount of γ, phase precipitation and the time of isothermal transformation is agreed
文摘The relationship between structure and hysteresis of phase transformation temperature in NiTi shape memory alloy has been investigated by means of TEM observation,positron an- nihilation and electrical resistivity measurement.The sequence of hysteresis for the alloy aged under different regimes was found to be:plate martensite>R-phase>tie-like martensite. The reversible displaeement of phase boundaries of these transformations is blocked by the co- herent stress field around Ti_(11)Ni_(14)phase particles.A linear relationship between S paramet- er of positron annihilation and maximum values of temperature hysteresis showed that the mismatch dislocation and elastic stress field established by Ti_(11)Ni_(14)phase precipitation are the main factor to determine the temperature hysteresis of phase transformation in NiTi shape memory alloy.
基金National Natural &ience Foundation of China!(No. 59671020).
文摘The microstructure and the stability of Fe_73.5Cu_1Nb_3Si_13.5B_9 alloy at different stages of phase transformation were investigated through the observation of X-ray difraction and transmission electron microscopy and the measurement of magnetic aftereffect (MAE). It was found that the dependence of the volume fraction of amorphous phase and the MAE in the samples annealed from 450 to 700℃ on the annealing temperature is similar.
