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I dont know whether to laugh, cry or hit my head against the wall at your posts. If money was the solution then Iam sure the Chinese would have been able to pay a 100 people a Couple of million a year and the engine problems would have been resolved. So why were they struggling and only after 20 yrs have now perhaps managed to get the engine sorted. Sometimes it is better to sit back and listen. India is importing an engine from US for the Tejas and if things were so easy whydont they manufacture one. Please dont indulge in useless arguments and sit back and read a little. We dont have any metallurgical base from where to even initiate the research. Then there are problems with specialized steels for which we only have one plant. Then the problem for generating turbine blades from a single crystal. These are metallurgical marvels and very closely guarded secrets.
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Chinese would have been able to pay a 100 people a Couple of million a year and the engine problems would have been resolved.
U mentioned about chines jet engine? here ar the list of chines jet engine, they r manufacturing since decades .
China's most powerful aircraft engine, the WS-20, is getting closer to finishing its tests. With a power output of 14 tons, the WS-20 will replace the less powerful and less efficient Russian D-30KP, which has only 10.5 tons of thrust. The WS-20 turbofan has been flying on this Il-76 test aircraft since 2014, and it's likely that aerial testing will wrap up in late 2015.
bbs.huanqiu.com
WS-20
The WS-20 turbofan engine can deliver up to 14 tons of thrust, which makes it comparable to the CFM-56 engine with powers Airbus 320 and Boeing 737s.
look that list of chines engine
https://en.wikipedia.org/wiki/List_of_Chinese_aircraft_engines
These are metallurgical marvels and very closely guarded secrets.
Test of the new type of engine on a flying platform
China has always been dependent on imported
aircraft engines, which China regards as a bottleneck in its development of advanced aircraft, especially its
stealth fighters that require engines better than imported ones.
As a result, China has allocated $16 billion special funding for
aircraft engine development.
Now, China Aviation News says in its report that China has successfully developed a new type of aircraft engine with better performance than imported ones.
The engineers working on it know well that in addition to good design, test is an indispensable procedure to ensure the success of their job.
In 2011 alone, over 1,000 hours of tests were carried out including two tests high up in the sky, which proved the high efficiency and quality of the engine.
https://chinadailymail.com/2015/05/...ines-now-exceed-performance-of-imported-ones/
sir every sort of research already done by western university , PAC dont need to do any further research on single crystal structure . What lacking behind is to install labs to test them and made them. A big set up of lab need that required funds. IF PAC spend these 200 million $ on labs they could start to develop single crystal blades
Nickel Based Superalloys
H. K. D. H. Bhadeshia
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superalloy is a metallic alloy which can be used at high temperatures, often in excess of 0.7 of the absolute melting temperature. Creep and oxidation resistance are the prime design criteria. Superalloys can be based on iron, cobalt or nickel, the latter being best suited for aeroengine applications.
The essential solutes in nickel based superalloys are aluminium and/or titanium, with a total concentration which is typically less than 10 atomic percent. This generates a two-phase equilibrium microstructure, consisting of gamma (γ) and gamma-prime (γ'). It is the γ' which is largely responsible for the elevated-temperature strength of the material and its incredible resistance to creep deformation. The amount of γ' depends on the chemical composition and temperature, as illustrated in the ternary phase diagrams below.
The Ni-Al-Ti ternary
phase diagrams show the γ and γ' phase field. For a given chemical composition, the fraction of γ' decreases as the temperature is increased. This phenomenon is used in order to dissolve the γ' at a sufficiently high temperature (
a solution treatment) followed by ageing at a lower temperature in order to generate a uniform and fine dispersion of strengthening precipitates.
The γ-phase is a solid solution with a cubic-F lattice and a random distribution of the different species of atoms. Cubic-F is short for
face-centred cubic.
By contrast, γ' has a cubic-P (primitive cubic) lattice in which the nickel atoms are at the face-centres and the aluminium or titanium atoms at the cube corners. This atomic arrangement has the chemical formula Ni3Al, Ni3Ti or Ni3(Al,Ti). However, as can be seen from the (γ+γ')/γ' phase boundary on the ternary sections of the Ni, Al, Ti phase diagram, the phase is not strictly stoichiometric. There may exist an excess of vacancies on one of the sublattices which leads to deviations from stoichiometry; alternatively, some of the nickel atoms might occupy the Al sites and vice-versa. In addition to aluminium and titanium, niobium, hafnium and tantalum partition preferentially into γ'.
Crystal structure of γ Crystal structure of γ'
The γ phase forms the matrix in which the γ' precipitates. Since both the phases have a cubic lattice with similar lattice parameters, the γ' precipitates in a cube-cube orientation relationship with the γ. This means that its cell edges are exactly parallel to corresponding edges of the γ phase. Furthermore, because their lattice parameters are similar, the γ' is coherent with the γ when the precipitate size is small. Dislocations in the γ nevertheless find it difficult to
penetrate γ', partly because the γ' is an atomically ordered phase. The order
interferes with dislocation motion and hence strengthens the alloy.
The small misfit between the γ and γ' lattices is important for two reasons. Firstly, when combined with the cube-cube orientation relationship, it ensures a low γ/γ' interfacial energy. The ordinary mechanism of precipitate coarsening is driven entirely by the minimisation of total interfacial energy. A coherent or semi-coherent interface therefore makes the microstructure stable, a property which is useful for elevated temperature applications.
The magnitude and sign of the misfit also influences the development of microstructure under the influence of a stress at elevated temperatures. The misfit is said to be positive when the γ' has a larger lattice parameter than γ. The misfit can be controlled by altering the chemical composition, particularly the aluminium to titanium ratio. A negative misfit stimulates the
formation of rafts of γ', essentially layers of the phase in a direction normal to the applied stress. This can help reduce the creep rate if the mechanism involves the climb of dislocations across the precipitate rafts.
The transmission electron micrographs shown below illustrate the large fraction of γ', typically in excess of 0.6, in turbine blades designed for aeroengines, where the metal experiences temperatures in excess of 1000oC. Only a small fraction (0.2) of γ' is needed when the alloy is designed for service at relatively low temperatures (750oC) and where welding is used for fabrication.
Transmission electron micrograph showing a large fraction of cuboidal γ' particles in a γ matrix. Ni-9.7Al-1.7Ti-17.1Cr-6.3Co-2.3W at%. Hillier, Ph.D. Thesis, University of Cambridge, 1984.
Transmission electron micrograph showing a small fraction of spheroidal γ' prime particles in a γ matrix.
Ni-20Cr-2.3Al-2.1Ti-5Fe-0.07C-0.005 B wt%. Also illustrated are M23C6 carbide particles at the grain boundary running diagonally from bottom left to top right.
Strength versus Temperature
The strength of most metals decreases as the temperature is increased, simply because assistance from thermal activation makes it easier for
dislocations to surmount obstacles. However, nickel based superalloys containing γ', which essentially is an intermetallic compound based on the formula Ni3(Al,Ti), are particularly resistant to temperature.
Ordinary slip in both γ and γ' occurs on the {111}<110>. If slip was confined to these planes at all temperatures then the strength would decrease as the temperature is raised. However, there is a tendency for dislocations in γ' to cross-slip on to the {100} planes where they have a lower anti-phase domain boundary energy. This is because the energy decreases with temperature. Situations arise where the extended dislocation is then partly on the close-packed plane and partly on the cube plane. Such a dislocation becomes locked, leading to an increase in strength. The strength only decreases beyond about 600oC whence the thermal activation is sufficiently violent to allow the dislocations to overcome the obstacles.
To summarise, it is the presence of γ' which is responsible for the fact that the strength of nickel based superalloys is relatively insensitive to temperature.
http://www.msm.cam.ac.uk/phase-trans/2003/Superalloys/superalloys.html
THE DEVELOPMENT OF SINGLE CRYSTAL SUPERALLOY TURBINE BLADES M. Gel& D. N. Duhl and A. F. Giamei Commercial Products Division Pratt & Whitney Aircraft Group East Hartford, Connecticut 06108 Single crystal superalloy turbine blades have recently entered production for JTSD commercial engine applications. This significant technical advance was made possible by the development of an alloy with improved properties and the development of a production casting process. The absence of grain boundary strengthening elements provided considerable alloying and heat treatment flexibility that resulted in single crystal Alloy 454 with an outstanding balance of properties. Major improvements in temperature gradients, the use of helical grain selectors, and the incorporation of these advances into existing vacuum furnaces have led to the rapid development of a production casting capability.
its not PAC has to carry on research they have to install labs and prepare the work force that are lenghty process. In Pak universities single crystal manufacturing is quite common. For example, JIK has mad many kind of single crystal alloys
http://www.tms.org/superalloys/10.7449/1980/superalloys_1980_205_214.pdf