Chapter 352: Bang! It broke!
"This is called pressurized solid-state recrystallization. The main driving force for grain growth comes from the interfacial energy of the polycrystal formed after rapid quenching."

Yu Yuncheng was a little confused after hearing this, but he didn't care for the moment. Gao Zhendong gave an explanation and told him to just go back and look for the answer in the book, although he might not be able to find it.

Seeing Gao Zhendong so confident, Yu Yuncheng was relatively optimistic about the credibility of this theory. At least this method, which sounded strange, was not completely without theoretical basis. Although he did not fully understand this theory yet, it seemed that Gao Zhendong at least understood it.

Seeing that he had at least accepted the principle of this method, Gao Zhendong told him the details.

"When annealing single crystals, the 'pulling' action has nothing to do with it. The main reason for choosing this method is that it does not require a crystallization control mechanism and the requirements for temperature control accuracy are not too high."

This was a pleasant surprise for Yu Yuncheng, as pulling the silicon single crystals was like attending the birth of a child.

The temperature is too high, it won't work; the temperature gradient is too large, it won't work; pulling too fast, it won't work; turning the crucible too fast, it won't work either.
When he heard that this method did not require crystal control, he suddenly felt as if the sky had brightened. This method was a good choice.

Then he heard some not-so-good news. As Gao Zhendong had said before, this thing was very time-consuming.

He needs to put the crystal ingot that has been directionally solidified after rapid quenching into an annealing furnace, or a recrystallization furnace, and burn it for 30 to 45 days. No, to days.

This annealing furnace is actually the pressurized stainless steel furnace that Gao Zhendong had just told him about.

"This process can eliminate the composition gradient at the microscopic level and the dendrite structure you have observed, and the grains grow to form single crystals. During this process, the temperature of the reaction tube or the mercury cadmium telluride compound must always be near its melting point, but it must be lower than the melting point, about 10 degrees, but it does not need to be controlled very precisely."

That's it?Gone?
Yu Yuncheng was very surprised. Is this all that matters? No other requirements.

After hearing his question, Gao Zhendong smiled and said, "Yes, there are no other requirements. Just stop when the time is up. The time can actually be optimized appropriately, but now we are doing research, so we require you to take out a part of the sample every 5 days for testing to feel the correspondence between time and crystal growth. Now our technical environment is poor and the conditions are insufficient. I think this method is the best. The requirements are simple, the crystal utilization rate is high, and the components are very uniform."

These features are the optimal solutions under the current environment. High crystal utilization can reduce prices.

Yu Yuncheng was happy. For this experiment, all he needed was a well-built furnace, hands and time.

But he still asked the question in his mind: "This method is so simple and the product is so good, so what is the cost?"

Any technology advances through trade-offs, just like 5G technology. Under the same other conditions, if you want high speed, you must give up wide coverage.

Shannon's Theorem: You are right.

Gao Zhendong said: "This method cannot grow crystals that are too large. Generally, the diameter will not exceed 15mm, and the length is only a few centimeters, but it is enough. There are also some other problems, such as impurities. When they are put in, no matter how many impurities there are, they will basically melt into the crystal. At the same time, there are many high-temperature defects, and the quartz tube itself may also form impurities in the crystal. But the important thing is that even so, as long as it is well controlled, this thing can be used."

In fact, as long as the method of preparing bulk crystals is used, no matter which one is used, mercury cadmium telluride cannot grow up, so the defect of small crystals does not matter, they are all equally bad, and the other things are not a big problem at this stage.

Although he didn't know where Gao Zhendong's confidence came from, Yu Yuncheng was very excited to see him speak so decisively. It seemed that this method, except for taking a longer time, was really the most appropriate method under the current conditions.

Even if there are some repetitions in the experiment, for him, spending half a year or a year is not a big deal.

Although according to Gao Zhendong's requirements, the main process of a test takes about 50 days, and if everything goes well, it can be completed in two months, but considering the modification of the pressurized furnace, possible repeated failures, etc., the six months to a year that Gao Zhendong said at the beginning is not an exaggeration.

Yu Yuncheng, who got the materials for the next crystallization process method from Gao Zhendong, came and left in a hurry and did not stay for a few days.

There is no way. This project cycle is really long and every bit of time must be saved.

However, before leaving, the comrades he brought with him used the single crystal furnace of the third rolling mill to pull out another batch of silicon dioxide.

The dosage is quite large and not enough.

By the way, they also took away a single crystal furnace approved by the ministry. That's right, as a participating unit of the single crystal furnace, they have only just been approved for one single crystal furnace.

Except for those needed by Factory 1274, all the products produced previously were put into production on site and put into operation as soon as they came off the production line, participating in the work of pulling a batch of silicon single crystals for the desert.
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This is an era of great enthusiasm and vigor. Gao Zhendong, Yu Yuncheng and others are busy, and similarly, others are not idle either.

In a laboratory of the Institute of Navigation and Research, a rocket engine is fixed on the engine test bench.

This test bench looked very simple. If Gao Zhendong were to take a look, it would be hard to tell that it was an engine test bench unless the engine was on it. The appearance of this thing was too different from the style of the Gufa test bench he had seen on the Internet in his previous life.

But don't say it's too crude, they can still test the items that need to be tested.

The engine is only about ten centimeters in diameter and is long and slender. It is exactly the engine used to imitate the infrared air-to-air combat missile.

Following an order from Mr. Song, the person in charge of the engine behind the bunker, a flame rose, smoke billowed, and a rumbling sound continued for a while.

As soon as the engine stopped working, a staff member laughed and said, "I don't know about other things, but the smoke is much smaller than our original one, hahahaha."

The comrade next to him looked at him and said: "That means that the ejected mass is not enough, and the thrust and specific impulse are worrying."

This comrade got anxious: "What does that mean? Is the ejected matter calculated based on this thing?" Several people laughed and seemed to be in a good mood.

Mr. Song said, "Stop laughing. Go check the data and print it out."

The data is basically stored in the computer center nearby. The Institute of Research and Development is very up-to-date and has connected most of the sensors to a DJS-59.

The program was written by them, and its main function is to automatically collect and store various data during the test and print them out when needed. The maximum acquisition frequency can reach 500Hz, which is a world of difference compared to previous data recording methods.

You should know that the working time of an air-to-air missile engine may even be only a few seconds. If you collect and observe data manually, you can just rub your eyes and remember some nodes such as peak values, but it is a bit of a fantasy to draw a curve.

Of course, when there were no computers available for data collection, the Institute of Research also came up with many ideas and researched a lot of equipment to ensure the measurement frequency and accuracy of the data.

As for the effect, it is not unusable, but compared with computers that automatically collect and record data, it is obviously not as good as others.

They have no shortage of transmission, but what they lack is high-speed data collection means.

Looking back, 500Hz is definitely not related to high-speed acquisition, but at this time it was really high-speed acquisition.

What the Institute of Guidance and Research is thinking of now is to get a DJS-60D specifically for this purpose. After all, that thing is much more convenient than the DJS-59. For example, it can be directly installed in the test field. This hope will soon be realized.

The 59th Ministry of Machine Building is recycling the existing DJS-60s. For every one recycled, they will be issued at least two DJS-Ds. For the Institute of Guidance and Research, this is a promising business.

Several comrades immediately went to the computer room. After a faint "sizzling" sound of printing, they ran back with the data, with happy faces.

Mr. Song took the data from them and scanned it.

"Working hours, X.Xs."

"Average thrust, XX kN"

"Gas pressure, X.XXMpa"

"Jet speed, XXXX m/s"

"."

After calculating in his mind using the formula he had already memorized by heart, Mr. Song was delighted: "Okay, according to this data, we can at least reach 13~15km!"

The distance that can be hit refers to the situation without considering the hit.

Although this distance is slightly worse than the 17km of Sidewinder, it is much better than the original Thunder-2.

This data is also normal. The propellant structure was originally a copy of the Sidewinder that was picked up. This time Gao Zhendong even got them the original STD propellant of the Sidewinder. It would be strange if it was not similar.

However, the people at the Guidance Research Institute did not know that this propellant was the original propellant of the Sidewinder fixed-fire missile. Before the test began, no matter how brave a person was, he would not have dared to imagine that he could get such data.

The comrades jumped for joy.

"So far? I can't imagine."

"Who would have thought that this thing is like a shot of chicken blood."

"Who said the thrust-to-impact ratio is worrying? Huh?"

"It's me, it's me, come on, I'll give you my face, hit me as much as you want, don't hold back, haha."

"."

At this time, a comrade who was checking the engine's working condition cried out: "Oh no! The throat liner is broken!"

When everyone heard this, it was as if a basin of cold water was poured over their heads, and they rushed over.

Excessive ablation is not a big problem, just make it a little thicker. Now the thrust and specific impulse are sufficient, and we are confident!
But if it's broken, that's another matter.

The engine's throat lining still uses the copper-silicon-infiltrated graphite that Gao Zhendong first developed with the help of the Northeast Carbon Research Institute. We all know its problems. If the working environment is harsh, the strength will decrease.

(End of this chapter)