Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7978135 | Materials Science and Engineering: A | 2015 | 19 Pages |
Abstract
The γⲠprecipitate plays a critical role in improving the mechanical properties of Ni-based superalloys. An undesirable phenomenon referred to as the Portevin-Le Chatelier (PLC) effect always appears in Ni-based superalloys deformed within specific ranges of strain rate and temperature. In order to systematically investigate the influence of the γⲠprecipitates on the PLC effect, four Ni-based superalloys with various γⲠcontents were designed and fabricated. Microscopic observations from transmission electron microscopy (TEM) indicated that the volume fraction of the γⲠphase was consistent with the designed value. Furthermore, analysis of energy dispersive spectroscopy (EDS) results revealed that the γ matrix of all the alloys consisted of the same components. Uniaxial tensile tests were performed at strain rates and temperatures ranging from 1Ã10â4 to 3Ã10â3 sâ1 and 300-500 °C, respectively. We found that the ultimate strength increased while the elongation decreased with increasing γⲠcontent. In addition, the serration changed from type A to type B and to type C with increasing temperature, decreasing strain rate or increasing γⲠcontent; the amplitude of type B serrations was described by unimodal or bimodal distributions. Increasing volume fraction of γⲠprecipitates shifted the region in which the PLC effect occurred, to the range of low temperatures and high strain rates. Moreover, the serration amplitude increased with increasing γⲠcontent at a given temperature, which indicated that the γⲠprecipitate increases the dynamic strain ageing (DSA) effect.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Yulong Cai, Chenggang Tian, Shihua Fu, Guoming Han, Chuanyong Cui, Qingchuan Zhang,