Effect of anisotropy on microstructure and high temperature stress rupture properties of Ni3Al base single crystal alloy
(1.School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics,Beijing 100083, China
2.北京市北京航空航天大学材料科学与工程学院)
2.北京市北京航空航天大学材料科学与工程学院)
Abstract: The effect of anisotropy on microstructure and high temperature stress rupture property of Ni3Al base single crystal alloy was investigated. The single crystal specimens were produced by screw selection crystal method. The microstructures were examined by OM, SEM, TEM and X-ray EDS techniques. The stress rupture tests were carried out in air by constant load creep machines under 1 100 ℃ and 130 MPa. The experimental results show that the dendrites preferential orientation deviates certain angles to heat flow orientation, and the secondary arms occur for different crystallographic orientations. The single crystal alloy with different orientations shows obvious anisotropy during tensile stress rupture tests under 1 100 ℃ and 130 MPa. The <111> orientation specimen has the best stress rupture life of 211 h. The high ductility at 1 100 ℃ of the <001> orientation specimen may be attributed to the most multiple equivalent slip systems.
Key words: Ni3Al; anisotropy; single crystal superalloy; stress rupture property