Internal friction （IF） spectra during reverse martensitic transformation from 35 to 135°C at different temperature rates of 0.5,0.75,and 1°C/min for Ti50Ni27Cu23 shape memory alloy （SMA） samples were mea...Internal friction （IF） spectra during reverse martensitic transformation from 35 to 135°C at different temperature rates of 0.5,0.75,and 1°C/min for Ti50Ni27Cu23 shape memory alloy （SMA） samples were measured with a dynamic mechanical analyzer,respectively.The IF spectra were characterized by IF peak increasing progressively and peak shifting toward high temperature with an increase in temperature rate.An iterative approach was used to calculate the precise intrinsic and approximate transitory IF contributions to the normal IF spectrum.The quantitatively analyzed results indicate that the transitory IF of this alloy is nonlinearly dependent on the temperature rate and obeys a power law with a power coefficient of 0.55.The predicted and experimental IF spectra at different temperature rates of 0.75 and 1°C/min agree well with each other,respectively.展开更多
A method of fuzzy identification based on T-S fuzzy model was proposed for predicting temperature Ms from chemical composition, austenitizing temperature and time for low alloy steel. The degree of membership of each ...A method of fuzzy identification based on T-S fuzzy model was proposed for predicting temperature Ms from chemical composition, austenitizing temperature and time for low alloy steel. The degree of membership of each sample was calculated with fuzzy clustering algorithm. Kalman filtering was used to identify the consequent parameters. Compared with the results obtained by empirical models based on the same data, the results by the fuzzy method showed good precision. The accuracy of the fuzzy model is almost 6 times higher than that of the best empirical model. The influence of alloying elements, austenitizing temperature and time on Ms was analyzed quantitatively by using the fuzzy model. It is shown that there exists a nonlinear relationship between the contents of alloying elements in steels and their Ms, and the effects of austenitizing temperature and time on Ms temperature cannot be neglected.展开更多
文摘Internal friction （IF） spectra during reverse martensitic transformation from 35 to 135°C at different temperature rates of 0.5,0.75,and 1°C/min for Ti50Ni27Cu23 shape memory alloy （SMA） samples were measured with a dynamic mechanical analyzer,respectively.The IF spectra were characterized by IF peak increasing progressively and peak shifting toward high temperature with an increase in temperature rate.An iterative approach was used to calculate the precise intrinsic and approximate transitory IF contributions to the normal IF spectrum.The quantitatively analyzed results indicate that the transitory IF of this alloy is nonlinearly dependent on the temperature rate and obeys a power law with a power coefficient of 0.55.The predicted and experimental IF spectra at different temperature rates of 0.75 and 1°C/min agree well with each other,respectively.
文摘A method of fuzzy identification based on T-S fuzzy model was proposed for predicting temperature Ms from chemical composition, austenitizing temperature and time for low alloy steel. The degree of membership of each sample was calculated with fuzzy clustering algorithm. Kalman filtering was used to identify the consequent parameters. Compared with the results obtained by empirical models based on the same data, the results by the fuzzy method showed good precision. The accuracy of the fuzzy model is almost 6 times higher than that of the best empirical model. The influence of alloying elements, austenitizing temperature and time on Ms was analyzed quantitatively by using the fuzzy model. It is shown that there exists a nonlinear relationship between the contents of alloying elements in steels and their Ms, and the effects of austenitizing temperature and time on Ms temperature cannot be neglected.
