Properties of NiTi wires with direct electric resistance heat treatment method in three-point bending tests
10.3760/cma.j.issn.1002-0098.2011.03.011
- VernacularTitle:直流电热处理对镍钛合金丝三点弯曲性能的影响
- Author:
Hong-Mei WANG
1
;
Bang-Kang WANG
;
Chao-Chao REN
;
Yu-Xing BAI
Author Information
1. 首都医科大学口腔医学院
- Keywords:
Orthodontic wires;
Three-point bending test;
Direct electric resistance heat treatment
- From:
Chinese Journal of Stomatology
2011;46(3):168-171
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the mechanical properties of Ni-Ti wires with direct electric resistance heat treatment(DERHT) method in three-point bending tests. Methods Two superelastic Ni-Ti wires(wire A: Smart SE, wire B: SENTALLOY SE, 0.406 mm ×0.559 mm) and 2 heat-actived Ni-Ti wires(wire C: Smart SM, wire D: L&H TITAN, 0.406 mm ×0.559 mm) were selected. They were heattreated using the DERHT method by a controlled electric current(6. 36 A) applied for different period of time[0(control), 1.0, 1.5, 2. 0, 2. 5 seconds). Then, a three-point bending test was performed under controlled temperature (37 ℃ ) to examine the relationships between the deflection and the load in the bending of wires. Results After DERHT treatment, the plateau in the force-deflection curve of superelastic Ni-Ti wires and heat-actived Ni-Ti wires were increased. When the wires were heated for 2. 0 seconds and deflected to 1.5 mm, the loading force of A, B, C and D Ni-Ti wires increased from (3.85 ± 0. 11 ),(3.62±0.07), (3.28±0.09), (2.91 ±0.23) Nto (4.33 ±0.07), (4.07 ±0.05), (4.52±0.08),(3.27 ± 0. 15 ) N respectively. Conclusions DERHT method is very convenient for clinical use. It is possible to change the arch form and superelastic force of NiTi wires. The longer the heating time is, the more the superelastic characteristics of the wires are altered.
