Synthesis In Situ Composite TiAl-Based with Particulate Al2O3 Reinforcement by Powder Metallurgy Route

2013 ◽  
Vol 858 ◽  
pp. 159-163
Author(s):  
Tran Duc Huy ◽  
Nguyen Hong Hai ◽  
Keiichi N. Ishihihara
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Matrix Material ◽  
High Temperature Strength ◽  
Market Place ◽  
In Situ Techniques ◽  
Specific Strength ◽  
Reaction Characteristic ◽  
Selection Of

A major effort has been made over last 20 or so years to introduce TiAl-based alloys into the market-place as engineering component. Recently, titanium aluminide based composites are competitive candidate for aerospace use due to the favorable properties of matrix material, such as low density, high specific strength and relative good properties at elevate temperature [1-4]. The amount of aluminum in titanium alloys exceeds that used in conventional alloys and can range from 10 to 48at%. This concentration of aluminum allows the formation of anin-situalumina reinforcement which is responsible for the excellent oxidation, sulfidation and carburization resistance at temperatures of 1000°C and higher. However, their brittleness and rapid crack growth rate at low to intermediate temperature hinders their application/3/. Nevertheless, nanostructure of monolithic TiAl is unstable at elevate temperatures which deteriorate the high temperature properties. In order to improve the high temperature strength of intermetallic, ceramic particles can be utilized as reinforcements [4, 5]. Recently, in-situ techniques have been utilized to fabricate TiAl-Al2O3composite through displacement reaction between TiO2and Al in planetary ball milling and subsequence heat treatment. The knowledge of reaction characteristic in the Al-TiO2system is great importance to optimize the processing/4, 6/. The chemical compatibility with the iron aluminide matrix at temperature above 1000°C is an important factor for the selection of reinforcements because extreme interfacial reaction during processing results in the degradation of mechanical properties [3, 4].

Microstructural characterization of plasma-processed Ti-Al metal matrix composites

1989 ◽  
Vol 47 ◽  
pp. 552-553
Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
M. A. Burke
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Plasma Processing ◽  
Microstructural Characterization ◽  
High Temperature Strength ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Long Time ◽  
Strength And Stiffness ◽  
Intermetallic Matrix Composites

Intermetallic matrix composites are candidates for ultrahigh temperature service when light weight and high temperature strength and stiffness are required. Recent efforts to produce intermetallic matrix composites have focused on the titanium aluminide (TiAl) system with various ceramic reinforcements. In order to optimize the composition and processing of these composites it is necessary to evaluate the range of structures that can be produced in these materials and to identify the characteristics of the optimum structures. Normally, TiAl materials are difficult to process and, thus, examination of a suitable range of structures would not be feasible. However, plasma processing offers a novel method for producing composites from difficult to process component materials. By melting one or more of the component materials in a plasma and controlling deposition onto a cooled substrate, a range of structures can be produced and the method is highly suited to examining experimental composite systems. Moreover, because plasma processing involves rapid melting and very rapid cooling can be induced in the deposited composite, it is expected that processing method can avoid some of the problems, such as interfacial degradation, that are associated with the relatively long time, high temperature exposures that are induced by conventional processing methods.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

Recent Advances in Development and Processing of Titanium Aluminide Alloys

2000 ◽  
Vol 646 ◽  
Author(s):  
Fritz Appel ◽  
Helmut Clemens ◽  
Michael Oehring
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Environmental Stability ◽  
Physical Metallurgy ◽  
Specific Strength ◽  
Wide Range ◽  
Structural Applications ◽  
Strength And Stiffness ◽  
Nickel Base

ABSTRACTIntermetallic titanium aluminides are one of the few classes of emerging materials that have the potential to be used in demanding high-temperature structural applications whenever specific strength and stiffness are of major concern. However, in order to effectively replace the heavier nickel-base superalloys currently in use, titanium aluminides must combine a wide range of mechanical property capabilities. Advanced alloy designs are tailored for strength, toughness, creep resistance, and environmental stability. Some of these concerns are addressed in the present paper through specific comments on the physical metallurgy and technology of gamma TiAl-base alloys. Particular emphasis is placed on recent developments of TiAl alloys with enhanced high-temperature capability.

Fibrous composites with high melting-point matrices

1970 ◽  
Vol 319 (1536) ◽  
pp. 33-44 ◽  
Keyword(s):  
High Temperature ◽  
Epoxy Resins ◽  
Base Alloy ◽  
High Temperature Strength ◽  
High Melting Point ◽  
Temperature Capability ◽  
Strength And Stiffness ◽  
Nickel Base ◽  
Fibre Matrix ◽  
Selection Of

It is now well established that the strength and stiffness of materials such as epoxy resins and aluminium can be increased by the incorporation of suitable fibres. However, relatively little effort has been made to improve similarly the high temperature strength of materials intended for service above ca . 800°C. This paper is introduced with a general examination of fibre/matrix systems that offer improved high temperature capability over current materials, with reference to gas turbine blade applications. The importance of properties and characteristics that influence the selection of suitable fibre and matrix combinations, for example, density, strength, oxidation resistance and compatibility, are discussed. Experi­mental work on the strength of potentially useful fibres such as refractory metal and alumina filaments, their incorporation into nickel-base alloy matrices using vacuum-casting techniques, and the evaluation of composites are described. In terms of the measured properties and of strength predictions based on fibre and matrix data, the merits and limitations of composites relative to well-developed alloys strengthened by precipitation mechanisms are considered.

scholarly journals Effect of microstructure on fatigue crack propagation in a titanium-aluminide alloy under thermomechanical fatigue conditions - Current activities in the subcommittee of Titanium-Aluminide alloys in the Society of Materials Science, Japan (JSMS) -

2020 ◽  
Vol 321 ◽  
pp. 11055
Author(s):  
Yasuhiro Yamazaki ◽  
Ryota Sugaya ◽  
Fumio Tooyama
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Titanium Aluminide ◽  
Collaborative Research ◽  
High Temperature Strength ◽  
Tial Alloys ◽  
Titanium Aluminide Alloys ◽  
Effect Of Microstructure

Titanium aluminide (TiAl) alloys have attracted to considerable interest as a material of blade in the low-pressure turbine section of aero engines since their superior specific strength. The mechanical properties and strengths of TiAl alloys are strongly sensitive to their microstructure controlled with thermo-mechanical processing. The collaborative research has been started from 2017 by the subcommittee on Titanium-Aluminide alloys, JSMS Committee on High Temperature Strength of Materials, in order to get basic information about the influence of microstructure on the high-temperature strength. This paper is a part of the collaborative research. The crack propagation tests were carried out under the load controlled out-of-phase type TMF (OP-TMF) loading condition with temperature range 400 ℃ -760 ℃ . The effect of microstructure on fatigue crack propagation behavior in was discussed.

Properties of In Situ Reinforced Silicon Nitride Ceramics

1991 ◽  
Vol 251 ◽  
Author(s):  
C.-W. Li ◽  
J. Yamanis ◽  
P.J. Whalen ◽  
C.J. Gasdaska ◽  
C.P. Ballard
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Metastable Phase ◽  
Abrasive Particle ◽  
Ceramic Matrix Composites ◽  
Ceramic Composites ◽  
High Fracture Toughness ◽  
High Temperature Strength ◽  
Nitride Ceramics

ABSTRACTIn situ reinforced (ISR) silicon nitride ceramics have been developed to have microstructures that mimic the best whisker containing ceramic matrix composites. Large, interlocking needle-like grains of beta silicon nitride can be produced throughout these materials to create an isotropic, high-temperature ceramic with high fracture toughness (˜9 MPa√m), good high-temperature strength (4 Pt MOR = 750 MPa at 25°C and 500 MPa at 1375°C), high Weibull modulus (m >20), and low creep at high temperature. Since these materials do not rely on transforming metastable phase inclusions as a toughening mechanism, their fracture resistance is virtually insensitive to temperature. The high crack growth resistance of these ceramics also yields a material which is extremely defect tolerant. Residual MOR strengths of 300–400 MPa are typical after multiple 50-kg Vicker's indentations of the sample tensile surface. After abrasive particle impact, the biaxial strengths of the in situ reinforced ceramics are typically more than twice that of traditional, fine-grained silicon nitrides.Unlike ceramic composites toughened using whisker additives, the in situ reinforcement approach to silicon nitride development does not require the use of complicated whisker dispersion techniques for green processing, nor is shape-limiting hot pressing required for densification during sintering.

scholarly journals High temperature strength of fiber-reinforced Ni3Al-Mo in situ composite.

1990 ◽  
Vol 39 (442) ◽  
pp. 878-882
Author(s):  
Chengguo WANG ◽  
Shiomi KIKUCHI ◽  
Yoshitaka OKITSU ◽  
Masahiro KOIWA
Keyword(s):  
High Temperature ◽  
High Temperature Strength ◽  
Fiber Reinforced ◽  
In Situ Composite
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