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Critical Acquisition from TEI & TÜBİTAK-MAM in Material Technologies

Issue 105

Within the scope of the KRİSTAL Project, which was supported by the R&D and Technology Management Department of the Presidency of Defense Industries and initiated with the cooperation of TEI and TÜBİTAK-MAM in 2016, and which covers the "single crystal blade casting" activities considered as a critical technology stage in turbine engines, the production of cooled and uncooled turbine blades to be used in TEI-TS1400’s high pressure turbine was completed and delivered to TEI.

Stating that TÜBİTAK-MAM and TEI will achieve a critical acquisition in material technology with the production of single crystal turbine blades, TÜBİTAK President Hasan MANDAL said, “In addition to such production, I also think that the competence and talent as well as the material technologies we have acquired here are important for the development and sustainability of our country, especially in the defense industry.”

MANDAL stated that together with TEI they developed delivered the first set of the turbine blades, which work under extreme conditions and he noted that sometimes these blades are impractical to import, he said “As TÜBİTAK-MAM, we are able to manufacture turbine blades, which are the most difficult component of our country's first domestic and national turboshaft engine. This is a critical technology owned by a very limited number of countries in the world. It is a very complex and difficult design, and it is not easy to manufacture and we have achieved it. TÜBİTAK Materials Institute and TEI will now be able to produce nickel-based superalloys for these and similar applications, starting from raw material, with the Aviation Engine Materials Development Project – Cevher Project - the contract of which was signed yesterday.” 

TEI President and CEO Prof. Mahmut F. AKŞİT expressed that he was also a Board Member of EÜAŞ (Electricity Generation Company) when he was a faculty member at Sabancı University and said that they took similar steps for blades required by industrial gas turbines at that time and that they brought this type of infrastructure to TÜBİTAK MAM.

AKŞİT pointed out that even if they sell the turbine blade, which is one of the most important parts of aviation engines, they do not share the technology and how it is produced, and he stated that they decided to develop the blade technology at TÜBİTAK-MAM because they knew the infrastructure there.

AKŞİT stated that the blades received today were not the first turbine blades manufactured by TÜBİTAK, they were previously delivered to TUSAŞ and that these blades were also used in the TEI-TS1400 engine, but they could not organize a ceremony at that time.

Stating that they received delivery of the previous turbine blades in stages as they were completed, AKŞİT said, “What you see here is a complete set for an engine. They are the first-stage single crystal blades, not having internal cooling, which is much more difficult to manufacture, and second-stage single crystal blades having internal cooling. We plan to use this on our TS5 engine. These blades were also used in the engines we previously supplied to TUSAŞ. This is the full set for our TS5 engine. It was the first time we see them all together as a full set.” 

Stating that they produced the TS4 engine and that the related tests are continuing, AKŞİT said, “We delivered our first national helicopter engine, the TEI-TS1400 on December 2, 2020. These blades will be mounted on our TEI-TS1400 engine (TS5) and they will work on the GÖKBEY helicopter.”  

AKŞİT pointed out that the first-stage blades come first when the most critical parts in an engine are listed and said, “Perhaps the combustion chamber comes second, followed by the second-stage blades in terms of temperature and technological complexity. The compressor side is also rather complex, but the most complicated parts are in the first-stage single crystal blades. If you can't do this, you can't generate power, you can’t achieve at high temperature.”

AKŞİT said the following regarding the function of single crystal turbine blades in engines: “All jet engines, like other fossil fuel engines, operate with the expansion of hot air. How do we heat air? We put fuel in it and ignite it so that the air gets heated and expands. To do this, we have to compress the air from the compressor. If we do not compress the air, the combustion will be very slow and we get much lower power from the same engine. The power we obtain per unit time decreases. That's why we reach high pressure; if it burns more efficiently, we get more output from the engine per unit time. As such, instead of using the gas that ejected from the back in direct impulse, we convert part of the energy there into rotational motion by having it hit these hot blades, which supports the compression by absorbing the air in the compressor. Without these blades, the engine is not able to run. In other words, these blades run the compressor by using considerable power.”

The single crystal casting blades produced by TÜBİTAK-MAM under the highest quality standards will first be used in the TS5 engine to be used in ground tests of the TEI-TS1400 engine. In subsequent stages of the project, it will be used in the certification processes, which are very critical for aviation industry, and later in the final engines.

Turbine blades, one of the most critical components of aviation engines, are exposed to high temperatures, versatile power sources and harsh environmental conditions, and as a result they need to protect the integrity of parts and the engine. They are produced from nickel-based superalloys with single crystal structure by a precision casting method and are suitable for working at temperatures up to 1400°C with their extremely sensitive cooling channel designs. Thanks to the single crystal casting, subsequent heat treatments and simultaneous development of non-destructive test methods, an important step will be taken in the acquisition of high technology