Y. Huo
,
Y. Chen
,
X. Zu and M. Tu( Department of Metal Materials
,
Sichuan University
,
Chengdu 610065
,
China)( Department of Metal Materials
,
Sichuan University
,
Chengdu 610065
,
China)( Department of Metal Materials
,
Sichuan University
,
Chengdu 610065
,
China)( Department of Physics
,
Sichuan University
,
Chengdu 610065
,
China)
金属学报(英文版)
In this paper, a theoretical model was presented to simulate the stress-strain hysteresis and the inner hysteretic behaviors, which were observed for polycrystalline Ni-Ti and Cu-based shape memory alloys (SMAs) at various temperatures. It was assumed that the stress-strum hysteresis of the grains of a polycrystalline sample of SMAs was relatively simple and easy to be calculated. The texture of the sample was characterized by a distribution function, which could be obtained from the experiments. Thercfore,the model provided a means to simulate and, for the first time, to predict the stressstrain hysteresis at different loading temperatures for polycrystalline SMAs.
关键词:
shape memory alloys (SMAs); hysteresis; mathematical modeling of phase transition
Y.H.Wen 1)
,
N.Li 1)
,
Y.G.Xu 1)
,
M.J.Tu 1)
,
P.Q.Li 2)
,
Y.L.Liu 2) and Y.L.Ma 2) 1) Department of Materials Shaping and Controlling Engineering
,
Sichuan University
,
Chengdu 610065
,
China 2) Xi'an Petroleum Pipe Research Institute
,
Xi'an 710065
,
China
金属学报(英文版)
The effects of quenching temperature on shape memory effect and microstructure of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy have been studied. The results show that both the shape recovery ratio and the recovery strain increased as quenching temperature increased, the amount of stress induced ε martensite in the process of cold work decreased with the increase of quenching temperature, the shape recovery ratio and the recovery strain reached maximum at 650℃, and then decreased rapidly with the further increase of quenching temperature,the stress induced ε martensite wholly disappeared at 1023K. But when the quenching temperature is higher than 1023K, the further increase of quenching temperature had little effect on shape recovery ratio, the amount and size of thermal induced ε martensite would increased with the further increase in quenching temperature. The shape memory effect can be improved by the moderate amount of pre exist ε martensite in the matrix before deforming.
关键词:
shape memory alloy
,
null
,
null
N. Li 1)
,
Y.H. Wen 1)
,
Y.G. Xu 1)
,
M.J. Tu 1)
,
P.Q. Li 2)
,
Y.L. Liu 2) and Y.L.Ma 2) 1) Department of Materials Shaping and Controlling Engineering
,
Sichuan University
,
Chengdu 610065
,
China 2) Xi'an Petroleum Pipe Research Institute
,
Xi'an 710065
,
China
金属学报(英文版)
The effect of quenching temperature on the recovery stress of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy has been studied. The results show that both the maximum recovery stress σ h in heating and the recovery stress σ c at room temperature after heating increased as increasing quenching temperature increased, both σ h and σ c reached maximum at 650℃, and then decreased rapidly with the further increase in quenching temperature,but the descent degree of σ c was far bigger than that of σ h; When the quenching temperature is higher than 850℃, the further increase in quenching temperature had little effect on them; At random quenching temperature, σ c was far bigger than σ h.
关键词:
shape memory alloy
,
null
,
null
Q.A. Li
,
H.Q. Mo
,
Y.Z. Huo
,
G. Sang
,
Y.F. Chen
,
M.G. Han
,
Y.G. Chen and M.J. Tu Department of Metal Materials
,
Sichuan University
,
Chengdu 610065
,
China
金属学报(英文版)
In this paper,a simulation model for the temperature field in the solidification process and microstructure distribution is presented. Then, the result of simulation for the final microstructure distribution is compared with experiment using 10-Kg ingot of MlNi3.55Al0.3Mn0.4CO0.75 (Ml: Lanthanum-rich Mischmetal) hydrogen stor- age alloy cast in a mould, which agrees with the experiment well. Finally, in order to obtain the expected as-cast microstructure distribution of 15-Kg ingot of MlNi3.55Al0.3Mn0.4Co0.75 alloy, the size of Cu mould is optimized using the model described. The optimized mould is then made and the alloy is cast in it, the expected as-cast microstructure distribution is obtained.
关键词:
hydrogen storage alloy
,
null
,
null
,
null
