A stent is employed to expand a narrowed tubular organ, such as a blood vessel. However, the persistent presence of a stainless steel stent yields several problems of late thrombosis, restenosis and chronic inflammation reactions. Biodegradable magnesium stents have been introduced to solve these problems. However, magnesium-based alloys suffer from poor ductility and lower than desired fatigue performance. There is still a huge demand for further research on new alloys and stent designs. Then, as fundamental research for this, AZ31 B magnesium alloy has been investigated for the effect of equal-channel angular pressing on the fatigue properties. ECAP was conducted for one pass and eight passes at 300 °C using a die with a channel angle of 90°. An annealed sample and ECAP sample of AZ31 B magnesium alloy were subjected to tensile and fatigue tests. As a result of the tensile test, strength in the ECAP (one pass) sample was higher than in the annealed sample. As a result of the fatigue test, at stress amplitude σ_a = 100 MPa, the number of cycles to failure was largest in the annealed sample, medium in the ECAP (one pass) sample and lowest in the ECAP (eight passes) sample. It was suggested that the small low cycle fatigue life of the ECAP (eight passes) sample is attributable to severe plastic deformation.

中文翻译：

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AZ31B镁合金等通道角压加工的疲劳性能

支架用于扩张狭窄的管状器官，例如血管。然而，不锈钢支架的持续存在会产生一些晚期血栓形成、再狭窄和慢性炎症反应的问题。已引入可生物降解的镁支架来解决这些问题。然而，镁基合金具有较差的延展性和低于所需的疲劳性能。对新合金和支架设计的进一步研究仍有巨大需求。然后，作为对此的基础研究，研究了AZ31 B镁合金等通道角挤压对疲劳性能的影响。使用通道角为 90° 的模具在 300 °C 下进行一次和八次 ECAP。对AZ31 B镁合金的退火试样和ECAP试样进行拉伸和疲劳试验。作为拉伸试验的结果，ECAP（一次通过）样品的强度高于退火样品的强度。作为疲劳试验的结果，在应力幅σ _a = 100 MPa，退火样品的失效循环次数最大，ECAP（一次通过）样品中，ECAP（八次通过）样品中最低。有人提出，ECAP（八道次）样品的低低周疲劳寿命小可归因于严重的塑性变形。