Effect of Orientation on Stress-Rupture Property and Related Deformation Microstructure of a Ni-Base Re-containing Singl
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Effect of Orientation on Stress‑Rupture Property and Related Deformation Microstructure of a Ni‑Base Re‑containing Single‑Crystal Superalloy at 900 °C Guang‑Lei Wang1,2 · Jin‑Lai Liu2 · Ji‑De Liu2 · Yi‑Zhou Zhou2 · Xu‑Dong Sun1 · Hai‑Feng Zhang1,2 · Xiao‑Feng Sun2 Received: 22 April 2020 / Revised: 18 June 2020 / Accepted: 7 July 2020 © The Chinese Society for Metals (CSM) and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Stress-rupture properties of a Ni-base Re-containing single-crystal superalloy with three orientations have been tested under 900 °C/445 MPa. An obvious anisotropy of stress-rupture property is attributed to orientation reliant deformation microstructure. The good strength in [001] orientation is attributed to the rapid multiplication of dislocations active in horizontal channels and later γ’ cutting via dislocations pair coupled with anti-phase boundary. The microtwin formation largely limits the strength and plasticity as a result of the continuous shearing across γ/γ’ microstructure by {111}〈112〉 slip activated in [011] orientation. The property in [111] orientation results mainly from the lateral cross-slip movements of the screw dislocations within connected matrix channels as well as the precipitate shearing by coplanar dislocations. Microcracks all initially originate from the interdendritic micropores in three orientations. The critical temperature of stress-rupture anisotropy could be increased by a high level of refractory solutes especially Re. Keywords Nickel-base superalloy · Stress-rupture property · Orientation effect · Deformation microstructure · Fracture behavior
1 Introduction Nickel-base single-crystal (SC) superalloys are widely employed to manufacture advanced aeronautic turbine and industrial gas rotor blades and vanes because of their outstanding creep and fatigue properties under corrosive and oxidized conditions at high temperature [1–3]. One advantage of this material results from the fact that (large angle) grain boundaries could be eliminated, attaining the enhanced properties. On the other hand, the compensation is their inherent anisotropy [1]. Nowadays, with the help of internal air-cooling passages and protective thermal barrier coatings, Available online at http://link.springer.com/journal/40195. * Jin‑Lai Liu [email protected] * Ji‑De Liu [email protected] 1
School of Materials Science and Engineering, Northeastern University, Shenyang 110004, China
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
2
the operating temperatures experienced by hollow blades and vanes with complicated shapes are various over a range from high temperature (as high as 1100 °C and above) at the tip down to low temperature (as low as about 750 °C) at the root and platform [4]. In addition, the local components in the blades and vanes are always subjected to different extents of axial centrifugal stresses combined with multi-axial thermal ones during service [4]. Therefore, the anisotropy in creep and fatigue properties is
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