标题：Fatigue behavior and mechanism of FV520B-I in ultrahigh cycle regime
作者：Zhang Ming; Wang Weiqiang; Wang Pengfei; Liu Yan; Li Jianfeng
作者机构：[Zhang Ming; Wang Weiqiang; Wang Pengfei; Liu Yan; Li Jianfeng] Shandong Univ, Sch Mech Engn, 17923 Jingshi Rd, Jinan 250061, Peoples R China.; [Zha 更多
会议名称：20th European Conference on Fracture (ECF)
会议日期：JUN 30-JUL 04, 2014
来源：20TH EUROPEAN CONFERENCE ON FRACTURE
关键词：FV520B-I; Ultrahigh cycle fatigue; S-N curve; Fatigue strength; Fatigue; life
摘要：FV520B-I which is a kind of martensitic precipitated hardening stainless steels is usually applied to manufacture centrifugal compressor impellers. The centrifugal compressor impellers may fail from ultrahigh cycle fatigue induced by wake flow. Aim to assess ultrahigh fatigue life of impellers, fatigue tests up to 10(9) cycles were carried out by ultrasonic fatigue testing machine to research ultrahigh cycle fatigue (UHCF) behavior and mechanism of FV520B-I. The results show that the S-N curve of FV520B-I can be divided into two segments at 10(7) cycles apparently. The fatigue cracks almost all initiated from the surface of an impeller when the fatigue life less than 10(7) cycles and then from the subsurface inclusion of an impeller when the fatigue life more than 10(7) cycles. In other words, the fatigue behavior of FV520B-I is in accordance with UHCF except one specimen's crack occurred at surface surprisingly when fatigue cycles greater than 10(7). Through the fracture morphology to be observed and measured, the reasons of "fish eye" area and GBF area formation were discussed, and the relationship of fatigue strength, fatigue life, and characteristic area size were researched by relative models. (C) 2014 Published by Elsevier Ltd.