Very-High-Cycle-Fatigue of in-service air-engine blades, compressor and turbine

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• 作者：A. A. Shanyavskiy (1)
  
• 关键词：subsurface ; fatigue crack ; Al ; alloy ; superalloy ; resonance ; quantitative fractography ; crack growth period ; stress level
• 刊名：SCIENCE CHINA Physics, Mechanics & Astronomy
• 出版年：2014
• 出版时间：January 2014
• 年：2014
• 卷：57
• 期：1
• 页码：19-29
• 全文大小：1,112 KB
• 作者单位：A. A. Shanyavskiy (1)
  
  1. State Centre for Flights Safety, Airport Sheremetievo-1, PO Box 54, Moscow Region, Chimkinskiy State, 141426, Russia
  
• ISSN：1869-1927

文摘

In-service Very-High-Cycle-Fatigue (VHCF) regime of compressor vane and turbine rotor blades of the Al-based alloy VD-17 and superalloy GS6K, respectively, was considered. Surface crack origination occurred at the lifetime more than 1500 hours for vanes and after 550 hours for turbine blades. Performed fractographic investigations have shown that subsurface crack origination in vanes took place inspite of corrosion pittings on the blade surface. This material behavior reflected lifetime limit that was reached by the criterion VHCF. In superalloy GS6K subsurface fatigue cracking took place with the appearance of flat facet. This phenomenon was discussed and compared with specimens cracking of the same superalloy but prepared by the powder technology. In turbine blades VHCF regime appeared because of resonance of blades under the influenced gas stream. Both cases of compressor-vanes and turbine blades in-service cracking were discussed with crack growth period and stress equivalent estimations. Recommendations to continue aircrafts airworthiness were made for in-service blades.