Chapter 1031 Laser Selective Melting

"Concentrate your efforts on conquering the material itself first?"

After hearing Chang Haonan's thoughts, Lu Qingsong's first reaction was disbelief:

"This is indeed more reasonable from a research perspective, but Mr. Chang, is it too late in terms of time..."

Processing on the basis of already obtained materials is much less work than starting from scratch... to develop a new material halfway.

Including the reverse engineering of 4722 alloy according to the original plan, it is also a relatively long-term task.

A sudden adjustment to the plan now will have a big impact on the entire project.

But right now, Chang Haonan really has no choice.

"no way."

He replied slightly helplessly:

"It is true that we are pressed for time, but since the attempt to use other titanium alloy substrates for testing and then push out the results has been proven to be unworkable, if we want to obtain the process parameters in a short time, we can only directly obtain enough 4722 alloy, establish a separate database and fitting formula for this series of materials, and the results will definitely be accurate. "

“Now the easiest way to get enough 4722 alloy is to ask Rolls-Royce according to the contract, but I don’t want to return all the processing waste to them, because too much will leak out... Therefore, we can only make two preparations.”

"On the one hand, we should focus most of our efforts on researching the 4722 alloy material itself. Although we may not be able to make blades exactly the same as Rolls-Royce in a short time, it is best to come up with base materials that meet the requirements, so that our computational modeling can The process can be completed using your own materials, and there is no risk of leakage..."

"Of course, on the other hand, the turbine processing task of the Trent 900 itself is definitely still the most important, so we cannot bet all our money on it. If the alloy forming process still does not improve by the end of this year, then we can only choose to ignore the British I want the second batch of follow-up samples..."

After hearing this explanation, Lu Qingsong nodded solemnly.

The principle of technical blockade is the same.

The main purpose is to increase the cost and time for others to catch up.

As long as the speed of technological iteration by latecomers is not as fast as mine, the entire market will still be in a monopoly state.

Therefore, if possible, everyone wants to prolong this process as much as possible.

After a slight hesitation, he continued:

"Then if Siro Company wants to know the progress...you know, it's Party A over there after all, and we can't possibly not disclose even a little bit of information..."

Chang Haonan's answer was almost without thinking:

"It is said that the process parameters are being adjusted... In addition, the several sets of scrap products processed in this round of testing can also be dismantled and handed over to them in several batches. It should be enough for two or three months..."

"..."

Just when the two of them were ready to deal with the worst-case scenario.

A figure appeared at the door of the office at just the right moment...

It's Hang Zhibin.

"Mr. Chang, and Gong Lu."

He held a folder that was almost the same as the one in front of Chang Haonan and walked in slowly:

"We trial-produced a batch of Ti-47Al-2Cr-2Nb based on the process we deduced from the data."

This sentence really shocked Chang Haonan and Lu Qingsong, who were still discussing this matter just now.

Especially the former.

I almost jumped out of my chair:

"Has trial production been produced? Bar or profile?"

We really can't blame Chang Haonan for being startled.

Mainly because less than 20 days have passed since the start of the research.

In such a short period of time, even developing a complete process based on existing experience is a bit difficult.

Not to mention the output material itself.

Even with the help of the system, it would not be possible so quickly...

Looking at the two people with shocked faces, Hang Zhibin also showed a blank expression for a moment.

Then I realized that the other person would be mistaken.

He quickly shook his head:

"How can there be profiles and rods... It's just a batch of metal powder made using the gas atomization process we developed in the past..."

After hearing his explanation, Chang Haonan breathed a sigh of relief. While he was glad that the scientific principles still existed, he also felt a little regretful.

Of course, even for powder, 20 days is a very good progress.

Therefore, he certainly cannot express his regrets:

"It doesn't matter. I have read the information provided by Rolls-Royce. The blade blanks are produced using laser selective melting and molding technology."

"With metal powder, at least we have a basis for further research on the molding process... In addition, Gong Lu and I are also considering adjusting the research and development plan, and we will concentrate our efforts with you to tackle base material production technology."

This laser selective melting molding process is a type of 3D printing.

It’s not really a new technology. It has been used in small quantities since the late 1990s.

However, at the beginning of the 21st century, it was not possible to directly produce finished products from powder as was done later.

They always create a rough blank first, and then carry out subsequent precision processing using traditional processing methods.

Although Hang Zhibin still doesn't know what happened specifically, for him, it will definitely not be a bad thing to have such two big guys joining.

So he nodded happily.

Then, he reported another progress quite excitedly:

"In fact, after the powder was made, we also conducted two rounds of powder spreading and molding tests... but the results were not very good, so they were not included in this report."

"But since you, Mr. Chang, are going to be in charge of this personally..."

Hearing this, Chang Haonan's eyes lit up again.

Without even waiting for the other party to finish, he hurriedly said:

"Tell me more!"

"Well... trial production, so we made 10mm cubic samples, but only the upper and lower surfaces of the samples were relatively flat, and the side walls, especially the side edges, showed obvious warping, burrs and unfused defects, and then from these defects..."

Because he did not bring the sample test report, Hang Zhibin could only describe it while organizing his words, so it was inevitable that he was a little stuck.

However, what he said was quite familiar to Chang Haonan.

So much so that he interrupted the other party in the middle:

"You mean, with the defects at these side edges as the source point, many macro cracks are generated, the kind that can be clearly observed by the naked eye?"

Hang Zhibin nodded immediately:

"Yes..."

Then he immediately realized something:

"Wait...How did you know, Mr. Chang?"

"Ah..."

Chang Haonan sighed:

"Because I also encountered almost the same problem here."

As he said, he handed the test report that Lu Qingsong had just brought to Hang Zhibin on the table:

"Take a look, there are pictures on it, are they the same as you..."

Chang Haonan's voice stopped abruptly halfway.

Because at this moment, an idea quickly passed through his mind, sparking a series of sparks of inspiration.

Laser selective melting molding is a proper use of laser thermal effect.

And his ultra-short laser processing is to minimize the effect of thermal effect.

But now both sides have the same problem...

As we all know, the direct cause of cracks is basically because the residual stress is greater than the tensile strength of the material itself.

However, the current picosecond laser is actually not enough to avoid all thermal effects.

In order to solve this problem, when Chang Haonan developed the ultrashort laser processing equipment, he immersed the workpiece to be processed in liquid.

If there is a similarity between the two processes of forming and processing, it is probably only this process.

It is not to say that the cooling method is the same-

It is certainly impossible to fill liquid during the powder forming process.

But the higher temperature difference itself makes its heat transfer efficiency close to liquid cooling.

That is, the cooling rate is close

In other words, the stress itself is likely to be generated during the cooling of the material.

In addition, the boundary between the unmelted powder and the molten powder will form a gap, increasing the surface freedom, so cracks are more likely to occur on the side of the sample. In contrast, since the upper surface is composed of the last melted molten pool, the surface quality is better and it is not easy to become a crack source.

This can explain why the upper surface of Hang Zhibin's cubic sample is relatively smooth, while the side edge part is the worst.

"Researcher Hang..."

After a long time, Chang Haonan slowly said:

"I seem to... think of a solution."