镍钛合金医疗器械产品疲劳测试断裂原因分析

Analysis on Fracture Cause of Nickel-Titanium Alloy Medical Devices Products in Fatigue Ttesting

镍钛合金医疗器械在疲劳测试结束后,发现波峰区域断裂,通过宏、微观对产品断裂原因进行分析。结果表明,产品断裂是由于丝材在编织前预热处理效果欠佳,导致编织波峰区域丝材产生塑性变形(出现微裂纹),致使材料强度降低,在周期性循环外力作用下,优先在微裂纹区域产生疲劳裂纹源,导致疲劳断裂。

The fracture of nickel-titanium alloy medical device was found in the wave peak area after the fatigue test.The fracture reasons of the products were analyzed by macro and micro analysis. The results show that the fracture of the product is due to the poor preheating treatment of the wire before braiding, leading to the plastic deformation(microcrack) of the wire in the braiding peak area,in which reduces the strength of the material. Under the action of cyclic external forces, the fatigue crack source occurs first in the microcracks area, leading to the fatigue fracture.