复合矫治弓丝接头的力学性能及接头组织观察

The investigation of mechanical properties and analysis of micro-structure on the joint of composite archwire

目的 测试复合矫治弓丝接头的机械性能及分析接头、接头断口变化。方法 测试复合矫治弓丝接头的拉伸强度、剪切强度、扭转强度、弯曲形变残余角,TiNi形状记忆合金丝超弹性,扫描电镜观察及分析接头、断口组织变化。结果 复合矫治弓丝接头抗拉伸强度为32 0～36 0MPa ,剪切强度为2 2 0～2 5 0MPa ,抗扭转强度为30～4 0N·m、断裂时扭转角度不小于1 4 4 0°,弯曲形变残余角为1 2～1 7°;钎焊异质接头中TiNi形状记忆合金丝超弹性几乎没有破坏;接头钎料与TiNi形状记忆合金界面不存在扩散层,与不锈钢丝界面之间有一较宽的扩散层,接头断裂多发生在钎料与TiNi形状记忆合金超弹界面处,部分发生在钎缝中心。结论 复合矫治弓丝机械性能符合正畸临床要求,可应用于临床。

Objective To investigate the mechanical properties and to analyze the micro-structure on the joint of composite archwire (CoAW).Methods The tension-resistance,cutting-resistance,distortion-resistance and remnant angle were tested by bending deformation of the CoAW joints,as well as the super-elasticity of TiNi shape memory alloy (TiNiSMA),then the histological changes of joints and the cross section of fractured surface of CoAW were observed under Scanning Electronic Microscope (SEM).Results The tension-resistance was 320～360MPa,distortion-resistance was 30-40·m, distortion angle in fracture was no more than 1440°,and remnant angle by bending deformation was 12～17°.There was little loss of super-elasticity of TiNiSMA.There was a wide defused stratum between the welding filler and stainless steel (SS),but not between the welding filler and TiNiSMA.The joint fracture was mostly located between the welding filler and TiNiSMA,partly in the center of welding crevice.Conclusion The mechanical properties of CoAW couldreach the demand of orthodontic practice ,CoAW can be used safely.