Great Country Academician

After a year passed, on the third day of the first lunar month, Xu Chuan returned to Qixia Controllable Nuclear Fusion Engineering Base.

The tearing of the magnetic surface during the fusion of deuterium-tritium raw materials, the choice of the first wall material, and the two biggest problems in the experimental stage of deuterium-tritium fusion ignition have all had their heads and ideas.

Once resolved, the construction of the demonstration pile can begin.

Strike while the iron is hot. Without knowing the progress of those Western countries' controllable nuclear fusion, what he can do is to speed up his pace as much as possible.

In the third year of junior high school, not only he returned to work, but also Zhao Guanggui's group who developed the first-wall carbon composite material, and researchers and engineers who came back after the annual vacation.

Qixia Institute of Controllable Fusion Engineering, Computational Materials Research Laboratory.

Xu Chuan found Zhao Guanggui, who was leading a team working hard to develop new carbon composite materials.

"How's the situation?" After finding Zhao Guanggui, Xu Chuan asked.

What he asked was naturally the research and development of new carbon composite materials using zirconia instead of hafnium oxide as a catalyst. After all, this is the key to hopefully solving the first wall problem.

Zhao Guanggui shook his head and said, "Not very ideal. Although the chemical properties of hafnium oxide and zirconium oxide are very similar, they are not the same substance after all."

"On the last day of the year, although we successfully used zirconia as a catalyst to produce a carbon composite material, the test results were not very good."

"No matter in terms of high temperature resistance or radiation resistance, it is not as good as carbon composite materials made of hafnium oxide as a catalyst, and the parameters cannot meet the requirements of the first wall."

Xu Chuan asked: "Does the problem appear in the special and unique arrangement of carbon nanotube hafnium crystal structure?"

Zhao Guanggui nodded and sighed softly: "Well, after replacing hafnium oxide with zirconium oxide as the catalyst, although carbon composite materials can also be produced, the uniquely arranged carbon nanotube hafnium crystal structure did not appear."

"Your previous speculation is correct. From this point of view, that special crystal structure is the key to greatly improving the high temperature resistance and radiation resistance of the hafnium oxide carbon composite material."

After thinking for a while, Xu Chuan said, "Take me to see the experimental data."

"Okay." Zhao Guanggui nodded, took Xu Chuan to another laboratory, and turned on a computer.

On the display screen, a piece of data was called out.

Zhao Guanggui stepped aside and said respectfully, "This is the test data. The time is tight. There are still some radiation resistance tests that have not been completed. It is estimated that it will take about three days to get the complete data."

Xu Chuan didn't care and said, "It's okay, I'll take a look first."

Sometimes, understanding the properties of a material does not necessarily require all the test data.

Compared with other things, he only needs to look at the scanning electron microscope image and related data of this new material.

The main reason for the failure of material research and development is that zirconium oxide failed to hook up with carbon atoms according to the ideal, and formed a specially ordered carbon nanotube hafnium crystal structure.

If you can find the reason and solve it, it's almost the same.

With his palm on the mouse, Xu Chuan swipe the data, and his eyes fell on the detection results of the scanning electron microscope.

Judging from the imaging image, the carbon composite material produced by replacing hafnium oxide with zirconium oxide as a catalyst and reinforcing agent does not have that special order of carbon nanotube hafnium crystal structure.

The carbon nanotubes in the material are piled up disorderly and disorderly. From the perspective of crystal structure, it is no different from the plate formed by pressing ordinary carbon nanotube powder.

That is to say, zirconia does not play a catalytic role in the material, and does not eutectic with carbon nanotube materials to form carbon nanotube zirconium crystals.

While flipping through the test data, Xu Chuan asked Zhao Guanggui beside him, "Have you speculated on the reason?"

With a wry smile, Zhao Guanggui said, "Yes, there are, but in a short period of time, we can't analyze any results at all."

"Theoretically speaking, both zirconium and hafnium belong to the lanthanide contraction element, with very similar chemical properties and the same arrangement of outer electrons. It should not be the case that hafnium can form a crystal structure, but zirconium cannot."

It is difficult to analyze a material and understand its formation cause and process from the perspective of physics, chemistry, and materials science.

What's more, they don't even know why hafnium oxide as a catalyst forms a unique carbon nanotube hafnium crystal structure in carbon composites.

In this case, it is very difficult to find out why zirconia cannot be used as a catalyst to co-grow carbon nanotubes and zirconium crystal structures.

Xu Chuan touched his chin and said, "Send me this test data, I'll go back and have a look first."

His attainments in materials are not comparable to ordinary materials researchers such as Zhao Guanggui. In theory, it is no problem for zirconium to replace hafnium and carbon nanotubes to form a unique crystal structure.

But now that there is a problem, it means there is a problem there.

He is going to take these data back to study and see if he can find the problem by calculating material mathematics.

Although the Chuanhai Materials Research Institute has a material calculation model, the model is dead and incomplete after all, and cannot take into account all aspects.

So he was going to study it himself.

With the data, Xu Chuan returned to the office.

For him, mathematics is not only an independent subject, but also a powerful scientific research tool to assist other subjects.

Although in many cases, especially in materials science, the results obtained through mathematical calculations cannot directly get the answer, but the relevant analysis can be used as a reference to help him avoid many detours when developing new materials.

Especially now, it is not necessary for him to analyze from beginning to end, it is enough to only deal with specific links.

Staring at the data and pictures in the computer, Xu Chuan fell into deep thought.

Although computing materials is his specialty, it is quite difficult to find out the problem that zirconia cannot co-exist with carbon nanotubes.

After thinking for a while, he picked up the ballpoint pen from the table

[GPAW pseudopotential: 1s22s22p6Zr3s23p64s23d104p65s24d2]

【e convergence: Ve=∫dru(R)ψ+0.05eV/(R)ψ(R)AB】

【eV particle convergence: p(R)=\u003cΦ|ψ+(R)ψ(R)|Φ10-6eV】

For computational materials science, if chemical precision is to be achieved through electronic-scale calculation methods, it is generally based on wave functions.

However, due to the limitation of calculation amount, it is often necessary to use alternative methods for non-bulk material properties such as interfaces, such as constructing thermodynamic phase diagrams. Considering the extremely complex potential energy surface, the dynamics is basically unsolvable.

In Xu Chuan's view, the nascent field of computing materials is actually very interesting.

Regardless of whether it is combined with experimental data, through the establishment of a mathematical model and then through numerical calculations, the actual process can be simulated and reproduced;

Or through computational simulation for specific materials, specific physical mechanisms or reaction mechanisms, directly through theoretical models and numerical calculations, predict, design or modify the structure and properties of materials.

These are all promising fields.

However, it still belongs to the territory waiting to be developed by the scientific community.

As the days progressed day by day, Xu Chuan locked himself in the office and used mathematical tools to theoretically improve the symbiosis of zirconia additives, while Zhao Guanggui continued to conduct experiments.

Others are also busy at their jobs nervously and orderly.

Time came to the twelfth day of the first lunar month. On the last day of the twelfth year, Xu Chuan finally completed the last step of calculation.

Looking at the calculations on the computer screen, a smile gradually formed on the corner of his mouth.

Where is the problem? Through calculation, he found it!

After checking the data and confirming that there was no problem, he reached for the phone and was just about to call Zhao Guanggui to ask him to come over when Zhao Guanggui appeared in the office.

"Academician Xu, the carbon composite material synthesized by using hafnium oxide as a catalyst, the neutron irradiation test results in Daya Bay have come out."

With a stack of materials, Zhao Guanggui walked up to Xu Chuan and reported the neutron irradiation results of the hafnium oxide carbon composite material.

Xu Chuan asked with a smile, "What was the result?"

Zhao Guanggui sighed, and said: "Very bad, low-energy neutron beams are very damaging to the sample material, with a neutron energy level of 3 MeV and a distance of 1.5 μm, the dpa reached 3.01, which is lower than that of the Austrian beam. .”

"And in the test temperature range from room temperature to 300 ° C, the reduction of area after irradiation is 73% to 80%"

DPA is a method to measure the degree of radiation damage of materials, which represents the ratio of the number of times atoms on the lattice are bombarded by particles to leave the original position to the number of atoms on the lattice.

3.01dpa means that each atom in the material is moved away from the original position 3.01 times on average.

It doesn't sound like much, but for the first wall material, this is already quite high data, not to mention that in the subsequent section test, the shrinkage rate reached more than 70%.

These data all imply that the performance of carbon composites decreases sharply after the crystal structure of carbon nanotube hafnium is damaged by neutron irradiation.

Hearing the news, Xu Chuan was not too surprised.

Years ago, he made speculations through his own simulation calculations, and determined that hafnium oxide carbon composite materials probably would not work.

Now the result came out, just as he expected before.

Smiling, Xu Chuan said, "How is the research on zirconia-carbon composite materials?"

Zhao Guanggui shook his head and sighed, "There hasn't been much progress, and I've let you down."

Xu Chuan smiled, clicked twice on the mouse with his right hand, then got up and walked towards the printer.

After waiting for a while, the document in the printer came out. He picked up the document, handed it over, and said with a smile, "It's okay, don't feel any pressure. This is a very difficult job in itself. There will be no work in a short time." It's progressing normally."

"Look at this first."

Zhao Guanggui took the printing paper with some doubts, and his eyes fell on it.

After seeing the things above clearly, his pupils shrank sharply.

"You found the problem?!"

Looking at the formulas and conclusions on the document, Zhao Guanggui couldn't restrain the shock in his heart and blurted out the question.

Xu Chuan nodded with a smile, and said, "In theory, yes, but it depends on the experimental situation."

After a pause, he continued: "I will leave the specific experiments to you. If possible, I hope you can lead someone to make these materials within five days, and then complete the test within a week."

"Because the slow neutron irradiation experiment at Daya Bay starts every month, and today is already the fourteenth day of the Gregorian calendar. If we miss it, we have to wait for another round, and the time will be too long."

The detection of the first wall material is actually quite troublesome.

First of all, ordinary physical properties, such as thermal conductivity, high temperature resistance, radiation resistance, etc., can be made at Qixia.

After confirming that these basic properties are passed, the material will be sent to Daya Bay for slow neutron irradiation testing.

If the results of the slow neutron irradiation test at Daya Bay are good, he will consider performing a real deuterium-tritium fusion high-energy neutron irradiation test in the dawn fusion facility.

After all, based on the current situation, every time Lixiao performs a real deuterium-tritium fusion ignition operation, it will cause some irreversible damage to the device.

To repair these damages, not to mention spending a lot of manpower, material resources and funds each time, it will take at least half a month or more in terms of time. If it is long, it may take a month.

And every shutdown of the Lixiao fusion device for maintenance is to lengthen the front of this 'controllable nuclear fusion competition'.

Hearing this, Zhao Guanggui straightened his body and replied with a serious face, "Don't worry, I will do my best!"

Xu Chuan nodded with a smile, and said, "That's fine, I'll leave this matter to you."

The Computational Materials Laboratory is productive.

In other words, after Xu Chuan found out why zirconia could not form the carbon nanotube hafnium crystal structure like hafnium oxide, the experiment progressed quite smoothly.

Zhao Guanggui led his team to lay the floor, sleep on reclining chairs and work overtime in the laboratory 24 hours a day. In just three days, the first batch of samples of carbon composite materials using zirconia as a catalyst were successfully produced. .

A piece of material was sent to different equipment, and various tests were carried out quickly. When the data from the scanning electron microscope appeared, Zhao Guanggui found Xu Chuan immediately, with a look of excitement and excitement.

"Professor, the scanning electron microscope data of the new material... came out!"

"Carbon nanotubes and zirconium atoms, similar crystal structures, formed!"

"We have hope!"

Panting heavily, Zhao Guanggui, who ran all the way over, used several words intermittently, completing his expression incoherently.

Xu Chuan got up and took the test data from him.

On the image of the scanning electron microscope, the special crystal structure of zirconium and carbon nanotubes is extremely conspicuous.

As for some other test data, although there are some errors and discrepancies between many values ​​and the results simulated by him through computational materials science methods, for example, the high temperature resistance range has been reduced to 3100 degrees, which is lower than that of carbon composite materials catalyzed by hafnium oxide. Nearly four Baidu.

But the high temperature resistance of 3100 degrees is enough for the first wall material.

As far as the test results are concerned, these samples are basically consistent with his previous calculation results.

Now, it's just the final touch!

Theoretically speaking, the carbon composite material that uses zirconium instead of hafnium as a catalyst can fully meet the performance of neutron radiation resistance.

Of course, the specific situation depends on the experimental results.

But at least, his calculations have never been wrong!

This time, hope is great!

After reading the test data in his hand, Xu Chuan smiled and praised: "Yes, thank you, I will arrange for someone to send the materials to Daya Bay for the first round of slow neutrons. Irradiation experiments."

"As for now."

After a pause, his eyes fell on Zhao Guanggui, who was full of black eyes and was a little unsteady on his feet, and then said: "Thank you for your hard work, go back and rest early, and take your time for the rest of the work."

It has to be said that more than half of the members of the materials research laboratory are middle-aged professors like Zhao Guanggui in their forties.

They are in the prime of life, energetic and experienced.

But no matter how young he is, after staying up late for ten days and a half months, he is really lucky not to collapse in the laboratory.