题　目：Factors controlling VHCF life of Ni-based single crystal superalloys

主讲嘉宾：Prof. Cormier Jonathan

时　间: 2021年5月26日（周三） 下午15:00

地　点: 郭可信楼109 (选课学生集中观看)

会议链接: https://us02web.zoom.us/j/85890714102?pwd=NUxFaHJnTWJhY2srbEw1Q2pETE9yZz09

会 议 ID: 858 9071 4102

会议密码: 3Ed4BT

 

ABSTRACT: Ni-based single crystal superalloys (SX) are widely used in gas turbine engines for the manufacturing of high pressure turbine blades due to their exceptional mechanical properties at high temperature. Service operations of blades may lead to fatigue controlled failure mechanisms due to the vibrations introduced by the gas flow in addition to the centrifugal forces. These failures are difficult to forecast, as up to 90% of the fatigue life is spent in the crack initiation phase. Typical frequencies of vibrations of airfoils are in between 1 and 10 kHz, requiring specific experimental facilities to achieve the very high cycle fatigue (VHCF) domain at high temperature. In this presentation, a critical analysis of the VHCF life sensitivity at 1000°C/20 kHz, R = -1 and R > 0.3 to the processing parameters (dendritic chemical homogeneity, casting pore size, introduction of a prior plastic deformation and γ/γ' microstructure degradation - i.e. γ' rafting) will be performed. For this, 10 different Ni-based SX alloys have been investigated, with different chemical compositions and/or processing parameters. A special attention will be paid in this presentation on the fine scale crack initiation mechanisms. By varying the casting process or the oxidation resistance among the different alloys studied, a map of crack initiation mechanisms in VHCF will finally be proposed for Ni-based SX alloys.

SPEAKER: Prof. Cormier was born in Jul. 1981 in French. He got PhD grant from the French Ministry of Armies under the supervision of Dr. José Mendez and Dr. Xavier Milhet in 2006 and cooperated with SAFRAN Helicopter Engines. He is the associate professor at ISAE-ENSMA since 2007. He won the FEMS Lecturer Award for Excellence in Materials Science and Engineering 2016-2017, FEMS-TMS International scholar award 2018, the TMS/AIME Champion Mathewson Award in 2019 and Chinese Academy of Science – IMR Lee Hsun Young Scientist Award 2020. He is the editor of Metallurgical and Materials Transactions A journal since Sept. 2016. He is also the member of the Program committee of 14th International Symposium on Superalloys/Superalloys 2020 (moved to 2021) and chairman of the 15th International Symposium on Superalloys/Superalloys 2024.