"For aero engine fan blade materials, there are currently three main materials."

"One is nickel-based materials like FGH4098-15, and then there are single-crystal superalloys, FGH4098 are also one of these materials, and the second is composite high-temperature materials."

“单晶高温合金当中，最主要的一点就是以单个晶体为单位，从而使得最终的材料合金化程度更高，以此来提高材料的各项性能，尤其是在高温环境下工作，甚至是在能够溶解的环境下进行工作时，也能够保证较强的性能。 ”

"That's the most important point."

For the vast majority of materials, when the temperature is high, their properties such as strength may have weakened, and the tensile strength has become low.

And such a material must not be used in aero engines.

In the case of single-crystal superalloys, the material can maintain its strength at high temperatures, and then it will not break suddenly when the turbine rotates at high speed.

"As for composite high-temperature materials, there are quite a few main types of materials, including resin-based, ceramic-based, carbon/carbon-based, and metal-based, but in terms of practical application, the ceramic base is still the best. ”

"So which one to choose......? That's a problem. ”

佘山科研院的材料实验室中，李牧坐在电脑前，搜索着各种各样的资料，心中微微思索着。

This question can be regarded as a problem in the selection of materials for aero engines, which makes every researcher have a headache.

After all, no one knows what kind of properties these different materials can have after different combinations.

It is not enough to resist high temperatures, otherwise, tungsten, a material with a melting point of more than 3400 degrees, has long been put on the aero engine.

It also has low density and low thermal brittleness, like tungsten, even if it can withstand high temperatures of more than 3,000 degrees, but it will become very brittle at 400 degrees, coupled with its extremely high density, it will basically not be considered for use in aero engines.

However, after thinking about it for so many days, Li Mu also had his own preliminary ideas.

"Nickel-based single-crystal superalloys are still relatively trustworthy."

At least there is already a mature example in front of him, and for Li Mu, what he can do at present is to use the successful cases of the past to assist.

For example, single-crystal superalloys were originally developed by a material strengthening method called dispersion strengthening.

没有太多的犹豫，李牧便做出了决定——先仔细分析现有的材料。

"So, let's first analyze the different properties of single-crystal superalloys with different properties in the interior."

As for where these materials come from, there is no need for Li Mu to worry, Cheng Guodong provided him with all kinds of information, including a variety of single-crystal superalloy materials that are being used by the military.

The information is very detailed, including a variety of metallographic diagrams, spectrograms, etc., which are basically available, even if they are relatively frivolous.

And this also provides a lot of convenience for Li Mu.

This is because, if you want to analyze materials using the theory of the electronic behavior of materials, the more detailed the information in this area, the better.

Therefore, as soon as he got started, Li Mu made a lot of progress.

A pile of scratch paper was full of all kinds of calculations, and Li Mu looked at these calculations and nodded with satisfaction.

“不错，现在基本上是从电子行为原理方面完全分析清楚了粉末高温合金能够在高温下仍然能够保持高强度的原理。”

"Under this special casting method, the harmful phase precipitation of this type of alloy at high temperature has been greatly alleviated, and the segregation of conventional alloys has been overcome."

"So...... Uniformity is paramount. ”

Li Mu's heart thought about it.

Ordinary alloys, because of the casting method, different components may have the problem of uneven distribution in its interior, so in the case of high temperature, these unevenly distributed components may be separated from the alloy and precipitated directly, so that the internal integrity of the alloy will be destroyed.

Just like that sentence, fortresses are breached from the inside, and the same is true of hard alloys, which appear independently of the particles, which naturally makes the high-temperature strength of the alloy worse and easy to break.

Li Mu took out one of the pieces from the information next to him, this information is the metallographic diagram of the fracture surface of a blade on the WS-22 that suddenly broke after high-speed operation in a long-term high-temperature environment.

It is easy to analyze that the harmful phases are the main culprits causing the breakage.

"This shows that the powder metallurgy process they use is still weak in terms of uniformity."

"Therefore, the goal is very clear, how to make the metal composition in the alloy more uniform, is a very important direction."

Li Mu casually wrote two words on the scratch paper: craftsmanship.

工艺的好坏，将成为合金均匀度的重要因素，也就对发动机性能有着十分巨大的影响，决定着发动机的寿命。

Like the life of the WS-15 engine, it is rumored that it is about 2,000 hours and 4,000 hours, but Li Mu has more detailed data here, which is about 3,600 hours.

And the key to determining this longevity is the blade material.

"The second goal is to continue to improve the formula."

"Hmm......"

This is actually relatively simple for Li Mu, using the computer in his mind, he can simulate day after day, and then according to the calculation of the principle of electronic behavior of the material, he can easily improve the current alloy formula.

But if the process does not change, there will definitely be problems.

"However, the process needs to be studied slowly, and the formula can be made out first, so that the new process can also be designed according to the new formula."

Thinking of this, Li Mu took action and began to design a new formula.

With the help of the computer in his mind, coupled with the help of new theories, after half a month, Li Mu came up with a new formula.

……

"This recipe...... Are you sure you can? ”

In the base, holding the new formula brought by Li Mu, the researchers of the four research institutes were all confused.

It has only been three weeks since they invited Li Mu, and he has come over with a new formula?

Real or fake?

Li Mu spread his hands: "You can use the supercomputer model to run it." ”

Hearing Li Mu say this, several people looked at each other, and then made a decision.

"Okay, let's try it first."

……

(End of chapter)