Chapter 1031 Laser Selective Melting Molding


    “Concentrate your efforts on conquering the material itself first?”


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


    “From a research perspective, this is indeed more reasonable, but Mr. Chang, is it too late in terms of time...”


    Performing processing on the basis of already obtained materials is always much less work than developing a new material from scratch...


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


    Sudden adjustments to the plan now will have a considerable impact on the entire project.


    But now, Chang Haonan really has no choice.


    "no way."


    He replied somewhat 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... so , 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..."


    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 latecomers’ technology iteration is not as fast as mine, the entire market will still be in a monopoly state.


    So, 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, so we can’t not disclose even a little bit of information..."


    Chang Haonan’s answer was almost without thinking:


    “Let’s just say 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 delivered to them in several batches. It should be enough to cope with 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...


    is Hang Zhibin.


    “Mr. Chang, and Gong Lu.”


    Hand holding a folder that was almost the same as the one in front of Chang Haonan, he walked in slowly:


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


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


    Especially the former.


    Nearly jumped out of the chair:


    “Has trial production been completed? Bar or profile?”


    It’s really not to blame that Chang Haonan was 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.


    Let alone 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.


    Immediately realized that the other party might have misunderstood.


    Hurryly shook his head:


    “How is it possible to have profiles and rods... We just used the aerosolization process we developed in the past to make a batch of metal powder...”


    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.


    Hence, he certainly cannot show his regret:


    "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 there is a basis for further research on the molding process... In addition, I Helu Gongzhi is also considering adjusting the R&D plan and concentrating our efforts with you to tackle base material production technology. "


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


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


    It’s just that at the beginning of the 21st century, it was not possible to directly produce finished products from powder as was done later.


    At first, a rough blank is almost produced, and then the subsequent precision processing is carried out through 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 also reported another progress quite excitedly:


    “Actually, after the powder was produced, 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 Mr. Chang, you are going to take charge of this personally…”


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


    He didn’t even wait for the other party to finish speaking, and said hurriedly:


    “Tell me more specifically!”


    "Well...it''s trial production, so what we make are 10mm cubic samples, but only the upper and lower surfaces of the samples are relatively flat. Obvious warping, burrs and unfused defects can be observed on the side walls, especially the side edges. Then From these shortcomings..."


    Since he didn’t bring the sample test report, Hang Zhibin could only organize the words and describe them at the same time, 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 want to say that the defects at these side edges are the source points, resulting in many macroscopic cracks that can be clearly observed by the naked eye?”


    ?Hang Zhibin nodded immediately:


    "right…"


    What I realized immediately was:


    “Wait a minute...Mr. Chang, how do you know?”


    "well…"


    Chang Haonan sighed:


    “Because I also encountered almost the same problem here.”


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


    “Take a look, there are pictures on it, does it follow you...”


    ?Chang Haonan''s voice stopped abruptly halfway through.


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


    ?Laser selective melting and molding properly utilizes the thermal effect of laser.


    The ultra-short laser processing on his side is to reduce the thermal effect as much as possible.


    But now the same problem has arisen on both sides...


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


    ??And the current picosecond laser is actually not enough to avoid all thermal effects.


    To solve this problem, when Chang Haonan originally developed ultra-short laser processing equipment, he immersed the workpiece to be processed in liquid.


    If you have to say where the two processes of molding and processing are similar, it would probably be this process.


    It’s not that the cooling methods are the same—


    It is of course impossible to fill liquid during the powder molding process.


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


    That is, the cooling rate is close to


    In other words, the stress itself is likely to be generated as the material cools.


    Furthermore, the boundary between the unmelted powder and the molten powder will form a gap, which increases the surface degree of freedom. Therefore, cracks are more likely to occur on the side of the sample. In contrast, since the upper surface is composed of the last molten pool, the surface quality is better and is less likely to become a source of cracks.


    This can explain why the upper surface of Hang Zhibin’s cubic sample is relatively smooth, while the side edges are in the worst condition.


    “Researcher Hang…”


    After a long time, Chang Haonan slowly said:


    “I seem to have thought of a solution.”


    (End of this chapter)