An Evaluation of the Creep Properties of an Al2O3/Ni3A1 Composite and the Effect of Disorder on Mechanical Properties

1992 ◽  
Vol 273 ◽  
Author(s):  
P. C. Brennan ◽  
W. H. Kao ◽  
J.-M. Yang

ABSTRACTOrdered Ni3A1 alloys and their composites are attractive materials for elevated-temperature structural applications due to their many favorable properties. The addition of alloying elements can significantly lower the Ni3Al order-disorder transition temperature and also result in the formation of a Ni solid solution. As the percentage of Ni solid solution increases, the composite's room-temperature flexural strength increases. The effect of rocessing parameters on the material's microstructure is discussed. The complex matrix microstructure also has a significant effect on the composite's creep properties. Normal power-law creep was exhibited by the composite material when tested in compression.

1990 ◽  
Vol 194 ◽  
Author(s):  
P. R. Subramanian ◽  
M. G. Mendiratta ◽  
D. B. Miracle ◽  
D. M. Dimiduk

AbstractThe quasibinary NiAI-Mo system exhibits a large two-phase field between NiAl and the terminal (Mo) solid solution, and offers the potential for producing in-situ eutectic composites for high-temperature structural applications. The phase stability of this composite system was experimentally evaluated, following long-term exposures at elevated temperatures. Bend strengths as a function of temperature and room-temperature fracture toughness data are presented for selected NiA1-Mo alloys, together with results from fractography observations.


2012 ◽  
Vol 736 ◽  
pp. 307-315 ◽  
Author(s):  
Murugavel Suresh ◽  
Satyam Suwas

Mg alloys show limited room temperature formability compared to its lightweight counterpart aluminium alloys, which is a main obstacle in using this metal for most of the structural applications. However, it is known that grain refinement and texture control are the two possibilities for the improvement of formability of magnesium alloys. Amongst the approaches attempted for the texture weakening, additions through of rare-earth (RE) elements have been found most effective. The relationship between the texture and ductility is well established. In this paper, the effect of rare earth addition on texture weakening has been summarized for various magnesium alloys under the two most common modes of deformation methods.


2021 ◽  
Vol 1023 ◽  
pp. 45-52
Author(s):  
Xiao Yan Wang ◽  
Meng Li ◽  
Zhi Xun Wen

After solid solution treatment at 1335°C for 4 hours and cooling to room temperature at different rate, the nickel-based single crystal superalloy were made into three kinds of nickel-based single crystal superalloy materials containing different size γ′ phases, respectively. The tensile test of I-shaped specimens was carried out at 980°C, and their effect of γ′ phase microstructure on the tensile properties was studied. The results show that the yielding strength of the material air-cooled to room temperature was lower than that with cooling rate at 0.15°C/s, but both of them were lower than the yielding strength of original material. Little difference was found on the elastic modulus of I-shaped specimens made of three kinds of materials. When the cubic degree of the γ′ phase is higher and the size is larger, the tensile properties of the material is better, which can be attributed to the larger size and narrower channel of the matrix phase that lead to higher dislocation resistance.


1991 ◽  
Vol 6 (8) ◽  
pp. 1779-1805 ◽  
Author(s):  
C.G. McKamey ◽  
J.H. DeVan ◽  
P.F. Tortorelli ◽  
V.K. Sikka

Fe3Al-based iron aluminides have been of interest for many years because of their excellent oxidation and sulfidation resistance. However, limited room temperature ductility (<5%) and a sharp drop in strength above 600 °C have limited their consideration for use as structural materials. Recent improvements in tensile properties, especially improvements in ductility produced through control of composition and microstructure, and advances in the understanding of environmental embrittlement in intermetallics, including iron aluminides, have resulted in renewed interest in this system for structural applications. The purpose of this paper is to summarize recent developments concerning Fe3Al-based aluminides, including alloy development efforts and environmental embrittlement studies. This report will concentrate on literature published since about 1980, and will review studies of fabrication, mechanical properties, and corrosion resistance that have been conducted since that time.


2019 ◽  
Vol 11 (11) ◽  
pp. 1489-1501
Author(s):  
Wenjing He ◽  
Caihe Fan ◽  
Shu Wang ◽  
Junhong Wang ◽  
Su Chen ◽  
...  

The evolution of nanoprecipitated phases in Al–Cu alloys under severe plastic deformation (SPD) is summarized in this study. SPD at room temperature induces the precipitation of Al–Cu alloys to dissolve, leading to the reformation of supersaturated solid solution in the aluminum matrix. In the process of SPD or aging treatment after the SPD, the reprecipitated phases are precipitated from the aluminum matrix and the mechanical properties of the alloys are remarkably improved. The mechanism and system of the redissolution of the precipitation phases and the effects of redissolution and reprecipitation on the microstructure and properties of Al–Cu alloys are comprehensively analyzed. The development and future of redissolution and reprecipitation of nanoprecipitated phases in Al–Cu alloys are also described.


2011 ◽  
Vol 236-238 ◽  
pp. 1939-1944
Author(s):  
Pei Qing La ◽  
Xin Guo ◽  
Yang Yang ◽  
Chun Jie Cheng ◽  
Xue Feng Lu ◽  
...  

Microstructure and mechanical properties of bulk nanocrystalline Fe3Al based alloy with 10 wt. % Mn prepared by aluminothermic reaction after annealing at 600, 800 and 1000°C for 8 h were investigated in order to gain insights in effects of annealing. Crystal structure of the alloy did not change and a fiber phase with enriched Mn appeared in the annealed alloy. Grain size of the alloy changed a little after annealing at 600°C but increased a lot after annealing at 800 and 1000°C. The annealed alloy had plasticity in compression at room temperature and the alloy annealed at 1000°C had yield strength of 782 MPa. The alloy without annealing has creep properties in compression at 800 and 1000°C and can be easily hot rolled to strip and sheet.


1998 ◽  
Vol 552 ◽  
Author(s):  
C. T. Liu ◽  
J. H. Schneibel ◽  
L. Heatherly

ABSTRACTMultiphase Mo silicide alloys containing T2 (Mo5SiB2), Mo3Si and Mo phases were prepared by both melting & casting (M&C) and powder metallurgical (PM) processes. Glassy phases are observed in PM materials but not in M&C materials. Microstructural studies indicate that the primary phase is Mo-rich solid solution in alloys containing ≤(9.4Si+13.8B, at. %) and T2 in alloys with ≥(9.8Si+14.6B). An eutectic composition is estimated to be close to Mo–9.6Si–14.2B. The mechanical properties of multiphase silicide alloys were determined by hardness, tensile and bending tests at room temperature. The multiphase alloy MSB-18 (Mo–9.4Si–13.8B) possesses a flexure strength distinctly higher than that of MoSi2 and other Mo5Si3 silicide alloys containing no Mo particles. Also, MSB-18 is tougher than MoSi2 by a factor of 4.


2006 ◽  
Vol 317-318 ◽  
pp. 611-614 ◽  
Author(s):  
Hao Wang ◽  
Tohru Sekino ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Koichi Niihara

Mullite-based iron nanocomposites were prepared by the reduction of a mullite-iron oxide solid solution and successive hot pressing. The solid solution was obtained from the heat treatment of diphasic gel by sol-gel method. Some of the α-iron nanoparticles have an intra-granular structure just after reduction. Mechanical properties are strongly affected by the content of iron. Low iron content is beneficial to strengthening while high iron content can improve the fracture toughness. Furthermore, the nanocomposites also behave ferromagnetic properties at room temperature.


1996 ◽  
Vol 460 ◽  
Author(s):  
A. L. R. Sabariz ◽  
G. Taylor

ABSTRACTThe intermetallic compound, RuAl with B2 CsCl type structure, has been shown to possess room-temperature toughness and plasticity. NiAl also forms a B2 compound and it is claimed that a pseudo-binary compound, (Ru,Ni)Al, may be formed because the difference in lattice parameter between the two binary phases is slight. In this work a study has been made of the mechanical properties of some polycrystalline compounds, across the RuAl-(Ru,Ni)Al pseudo-binary, prepared from high-purity elemental powders. Compressive yield stresses were measured between room-temperature and 900°C, and the mechanisms of plastic flow are discussed in relation to the dislocation structures observed by TEM. Hot-microhardness tests were made to provide an indication of the effect of solid-solution hardening.


2011 ◽  
Vol 284-286 ◽  
pp. 638-641
Author(s):  
Jun Cong Wei ◽  
Xiao Cui Han ◽  
Chun Hui Gao ◽  
Jian Kun Huang ◽  
Jun Bo Tu

MgO-Al2O3-TiO2 composite refractories were prepared by using magnesium aluminate spinel (MgAl2O4) and titanium dioxide as main starting materials and being sintered at high temperature. The influences of titanium dioxide additions on the room temperature physical properties, phase composition and microstructure were investigated. The phase composition and microstructure were tested by means of XRD and SEM. The results revealed that with increasing TiO2 content, the densification of the composites first increased sand then decreased and maximized at 4% TiO2 loading. This showed appropriate amount of TiO2 could contribute to the sintering of the composites due to the solid solution of TiO2 in magnesium aluminate spinel.


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