Mechanical properties of Ni3(Si,Ti) polycrystals alloyed with substitutional additions
- 60 Downloads
The mechanical properties of the L12-type Ni3(Si, Ti) polycrystals, which were alloyed with 1–2 at% of various transition metals and also doped with boron, were investigated over a wide range of temperatures. The addition of Hf enhanced the levels of yield stress whereas the addition of Cr, Mn and Fe reduced the levels of the yield stress over a wide range of temperatures. Ni3(Si, Ti) alloyed with Cr, Mn and Fe showed a shallow minimum in the yield stress-temperature curves. This result was correlated with the modification of the micro-cross-slip process by the additives. At low temperatures, the addition of Hf and Nb slightly reduced the elongation, while the addition of Cr, Mn and Fe improved elongation. This elongation behaviour was interpreted as the alloying effect on the intergranular cohesive strength of L12 ordered alloys. At high temperatures, the elongation of Ni3(Si, Ti) alloyed with Hf showed a particularly high value. This elongation behaviour is discussed based on the alloying effect on the competition between dynamic recrystallization and cavitation at grain boundaries. The fracture surfaces exhibited a variety of fracture patterns, depending on temperature and the alloy, and were primarily well correlated with the elongation behaviour. The ductilities of most of the alloys at high temperatures were reduced by the tests in air.
KeywordsPolymer Mechanical Property Boron Recrystallization Ductility
Unable to display preview. Download preview PDF.
- 1.T. Takasugi, M. Nagashima andO. Izumi,Acta Metall. Mater. 38 (1990) in press.Google Scholar
- 3.S. Hasegawa, T. Takasugi andO. Izumi, to be published.Google Scholar
- 11.O. Izumi andT. Takasugi, in “Proceedings of the MRS Symposium on High-Temperature Ordered Intermetallic Alloys II”, Pittsburgh, edited by N. S. Stoloff, C. C. Koch, C. T. Liu and O. Izumi, Vol. 81 (1987) pp. 173–82.Google Scholar