材料科学与工程学报
材料科學與工程學報
재료과학여공정학보
MATERIALS SCIENCE AND ENGINEERING
2007年
6期
917-921
,共5页
Ti-50.5Ni alloy%TGA treatment%dislocations%precipitates%temperature dependence of elongation
Transformation behavior and shape memory characteristics of a temperature gradient annealing(TGA) treated Ti-50.5Ni(at%) alloyhave been investigated by means of differential scanning calorimetry(DSC) and thermal cycling tests under constant load. By annealing the specimen under the temperature gradient from 823 K to 658 K after solution treatment, the B19' martensitic transformation start temperature changed by 60 K along the length of sample (150mm). Temperature dependence of transformation elongation (dε/dT) of the TGA treated wire was found to be 0.16 %/K. By annealing the specimen under the temperature gradient from 823 K to 658 K after 47 % cold working without solution treatment, the B19' martensitic transformation start temperature changed by 61K along the length of sample(150mm). Temperature dependence of transformation elongation (dε/dT) of the TGA treated wire was found to be 0.04 %/K. The large decrease in dε/dT by cold working effect suggested that an introduction of dislocation was more effective than precipitates for lowering dε/dT.
