Differential scanning calorimetry analyses of phase transformations in different nickel-titanium orthodontic wires
10.3321/j.issn:1002-0098.2008.05.013
- VernacularTitle:九种镍钛矫正弓丝相变温度的对比研究
- Author:
Yu-Xing BAI
1
;
Chao-Chao REN
;
Hong-Mei WANG
;
Yu-Feng ZHENG
;
Yan-Bo WANG
;
Song LI
Author Information
1. 首都医科大学口腔医学院
- Keywords:
Orthodontic wires;
Phase transition;
Nickel-titanium alloy
- From:
Chinese Journal of Stomatology
2008;43(5):302-305
- CountryChina
- Language:Chinese
-
Abstract:
Objective To characterize austenite,martensite and R phase temperatures as well as transition temperature ranges of the commonly used nickel-titanium(NiTi)orthodontic arch wires selected from several manufacturers.Methods Differential scanning calorimetry(DSC) method was used to study the phase transformation temperatures and the phase transition processes of 9 commonly used NiTi alloys (types:0.406 mm,0.406 mm×0.559 mm).Results The austenite finish temperatures of A,B,D NiTi wires were 22.4℃.21.9℃,22.5℃,respectively.No phase transformation was detected during oral temperature.It indicated that these types of NiTi wires did not possess shape memory property.For C and H NiTi wires,no phase transformation was detected during the scanning temperature range,suggesting that these two types of wires did not possess shape memory either.The austenite finish temperatures of E,G and I NiTi wires were 34.3℃,36.6℃,38.5℃,respectively,which were close to the oral temperature and presented as martensitic-anstenitic structures at room temperature,suggesting that the NiTi wires listed above had good shape memory effect.Although F NiTi wire also showed martensitic-austenitic structures at room temperature.its austenite finish temperature(61.5℃)was much higher than oral temperature.Conclusions The transformation phase temperatures and transformation behavior were varied among different NiTi alloys,leading to variability in shape memory effect.
