Microstructure and Mechanical Properties of Dual Two-Phase Intermetallic Alloys Composed of GCP Ni3Al and Ni3V Phases containing Nb

2006 ◽  
Vol 980 ◽  
Author(s):  
Wataru Soga ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi

AbstractDual multi-phase intermetallic alloys composed of Ni3X (X: Al and V) containing Nb were developed, on the basis of the Ni3Al-Ni3Nb-Ni3V pseudo-ternary alloy system. The dual multi-phase intermetallic alloys were characterized by scanning electron and transmission electron microscopies. High-temperature compression and tension tests, and compression creep test were conducted. It was found that the dual multi-phase intermetallic alloys show high yield and tensile strength with good temperature retention, accompanied with reasonable tensile ductility. The compression creep test conducted at high temperature showed lower creep rate in the dual multi-phase intermetallic alloys than in conventional Ni-base superalloys. The obtained results are superior to the dual multi-phase intermetallic alloys containing Ti.

2006 ◽  
Vol 980 ◽  
Author(s):  
Takayuki Takasugi ◽  
Yasuyuki Kaneno

AbstractDual multi-phase intermetallic alloys composed of Ni3Al (L12)+Ni3V (D022) phases were developed, based on the Ni3Al-Ni3Ti-Ni3V pseudo-ternary alloy system. High-temperature tensile deformation, fracture behavior, and compression and tension creep were investigated using polycrystalline and single crystalline materials. The alloys with such a novel microstructure show extremely high yield and tensile strength with good temperature retention, and also reasonable tensile ductility. Also, creep test conducted at high temperature showed extremely low creep rate and long creep rupture time. The obtained results are promising for the development of a new-type of high-temperature structural material exceeding conventional superalloys.


2011 ◽  
Vol 1295 ◽  
Author(s):  
T. Moronaga ◽  
Y. Kaneno ◽  
H. Tsuda ◽  
T. Takasugi

ABSTRACTDual two-phase intermetallic alloys based on the Ni3Al-Ni3V pseudo-binary alloy system have been reported to display high phase and microstructure stabilities and good mechanical properties at high temperature and are therefore considered to be used as a next generation type of high temperature structural materials. The microstructure of the dual two-phase intermetallic alloys is composed of primary Ni3Al and the channel (eutectoid) regions consisting of Ni3Al+Ni3V. In this study, the microstructure of the channel regions was investigated by a transmission electron microscope (TEM). The contrasts of the channel regions showed a complicated microstructure in bright-field images. However, the electron beam diffraction consisted of a single set of patterns and the spots did not accompany streaks, indicating that crystallographic coherency among the constituent phases or the domains is very high. It was also shown that the lattice misfit between the a-axis of Ni3Al and the c-axis of Ni3V is larger than that between the a-axis of Ni3Al and the a-axis of Ni3V. From the dark-field observation, it was found that the c-axis of Ni3V domains in the channel regions is oriented perpendicular to the interface between primary Ni3Al and Ni3V. Therefore, it is suggested that the crystallographic orientation of Ni3V in the channel regions is aligned in the manner of lowering an internal stress caused by the lattice misfit between primary Ni3Al precipitates and Ni3V domains.


2007 ◽  
Vol 127 ◽  
pp. 161-166
Author(s):  
Takayuki Takasugi ◽  
Yasuyuki Kaneno

Dual multi-phase intermetallic alloy, which is composed of Ni3Al(L12) and Ni solid solution (A1) phases at high temperature annealing and is additionally refined by a eutectoid reaction at low temperature annealing, according to which the Al phase is transformed into the Ni3Al(L12)+Ni3V(D022) phases, was prepared. High-temperature tension and creep test were conducted using single crystalline materials. The alloy with such a novel microstructure showed extremely high yield and tensile stresses with good temperature retention. The creep test conducted at high temperature showed extremely low creep rate and creep rupture time when compared with advanced Ni-based superalloys. The results obtained are promising for the development of a new-type of high-temperature structural materials.


2007 ◽  
Vol 561-565 ◽  
pp. 375-378
Author(s):  
Takayuki Takasugi ◽  
Yasuyuki Kaneno

Dual two-phase intermetallic alloys composed of geometrically close packed (GCP) structures of Ni3Al(L12) and Ni3V(D022) containing Nb were investigated in terms of the microstructural evolution during low temperature annealing (aging) and the related mechanical properties. The eutectoid region, i.e. the prior Al phase (Ni solid solution) is composed of the lamellar-like structure consisting of Ni3Al(L12) and Ni3V(D022) phases. The lamellar-like structure tended to align along <001> direction and on {001} plane in the prior A1 phase (or the L12 phase). In a wide range of temperature, the dual two-phase intermetallic alloys showed high yield and tensile strength, and also reasonable tensile ductility, accompanied with ductile fracture mode.


2011 ◽  
Vol 1295 ◽  
Author(s):  
T. Moronaga ◽  
S. Ishii ◽  
Y. Kaneno ◽  
H. Tsuda ◽  
T. Takasugi

ABSTRACTTwo-phase intermetallic alloys composed of geometrically close packed (GCP) Ni3Al (L12 phase) and Ni3V (D022 phase) have attractive mechanical properties at high temperature, and are therefore considered to be used as high temperature structural materials. In this study, the effect of Ta and Re addition on the microstructure and hardness of two-phase intermetallic alloys was investigated. The addition of Ta remarkably enhanced the hardness due to solid solution hardening of the constituent phases. On the other hand, the addition of Re retarded the formation of the two-phase microstructure, resulting in the lowest hardness in the solution treated condition. By aging at 1223 K, the Ni solid solution in the Re added alloy decomposed to Ni3Al and Ni3V, accompanied by precipitates of a Re-rich phase. Consequently, the hardness rapidly increased with increasing aging time. Simultaneous addition of Ta and Re induced very fine precipitates of a Re-rich phase after aging, and consequently resulted in a higher hardness than by the addition of Ta or Re alone.


2015 ◽  
Vol 1760 ◽  
Author(s):  
Yuki Hamada ◽  
Yasuyuki Kaneno ◽  
Hiroshi Numakura ◽  
Takayuki Takasugi

ABSTRACTThe effect of Si addition on microstructure and mechanical properties of dual two-phase intermetallic alloys was investigated. Si was added to the base alloy composition Ni75Al9V13Nb3 + 50 wt. ppm B by three substitution ways in which Si was substituted either for Ni, for Al and for V, respectively. The alloys added with 1 at.% Si showed a dual two-phase microstructure composed of Ni3Al (L12) and Ni3V (D022) phases, while the alloys added with over 2 at.% Si exhibited the same dual two-phase microstructure but contained third phases. The third phases were G phase (Ni16Si7Nb6) and A2 phase (the bcc solid solution consisting of Nb and V). Yield and tensile strength of the 1 at.% Si-added alloys were high in the alloy in which Si was substituted for Al but low in the alloys in which Si was substituted for Ni or for V, in comparison with those of the base alloy. Tensile elongation was lower than that of the base alloy irrespective of substitution ways. The density of the Si added alloys was close to or slightly lower than that of the base alloy. Oxidation resistance of the Si added alloy was increased. Si addition to the dual two-phase intermetallic alloys is beneficial for reducing the density and enhancing the oxidation resistance without a harmful reduction of strength properties.


2010 ◽  
Vol 654-656 ◽  
pp. 452-455
Author(s):  
K. Kawahara ◽  
T. Moronaga ◽  
Yasuyuki Kaneno ◽  
A. Kakitsuji ◽  
Takayuki Takasugi

The microstructures and hardness property of dual two-phase intermetallic alloys that arecomposed of various kind of volume fractions of geometrically closed packed (GCP) Ni3Al(L12) and Ni3V(D022) phases were studied. The hardness of dual two-phase intermetallic alloys basically was explained by mixture rule in hardness between primary Ni3Al precipitates and eutectoid region.Nb and Ti addition raised the hardness of dual two-phase intermetallic alloys by solid solute hardening in the constituent phases.The additional hardening arising from interfacial area between primary Ni3Al precipitates and eutectoid region was also found. As temperature increases, theadditional hardening decreased for the base and Nb added alloys but decreased little for the Ti added alloys.


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