The Literary Life of a Science Leader

Chapter 162 Plastic Deformation of Metals

The laboratories of the School of Mechanical Engineering are larger than those of the School of Materials because there are more and larger mechanical equipment than those of the School of Materials, so the design of the laboratory is also wider.

Mu Jingchi should be the last boss to arrive. When he came to the laboratory under the guidance of Ai Xiaosheng, many bosses were already in the laboratory.

The mechanical equipment is still running, and the brand-new metal plate is processed, and the bosses are all around the metal plate for testing.

"Didn't you go home? Why are you here so late?"

Yang Wenwu was the first to notice Mu Jingchi's arrival, and asked casually.

"I went shopping with my girlfriend, and there was a traffic jam on the way back, so I came here a little late." Mu Jingchi looked at the crowd around him, and unexpectedly found Director Hao, Gao Mingsong and Xu Shiquan from the military professor.

It is estimated that when they did not leave, they happened to encounter the matter of the School of Mechanical Engineering.

"What are the test results now?"

It's not too polite, everyone is from the research group, and there are quite a few contacts, basically they are acquaintances, so Mu Jingchi went straight to the core and asked.

"Professor Dong, Professor Dong?"

Yang Wenwu did not answer Mu Jingchi directly. Instead, he led Mu Jingchi into the crowd and saw Professor Dong Xinren who was explaining to the leaders of Huaqing University, the Ministry of Industry and Information Technology, and the Ministry of Science and Technology.

"Dr. Mu, you are here!" Hearing Professor Yang Wenwu's shout, Dong Xinren turned his head and saw Mu Jingchi, with a smile on his face, he hurriedly greeted Mu Jingchi joyfully.

"It looks like the result is very good!"

Mu Jingchi first greeted the various leaders, and seeing Professor Dong's expression, he knew that it was probably close, and it should be a good result.

There are so many big bosses, if the result is not good, there will be a quarrel long ago.

"Yes, we have found the exact method!" Professor Dong Xinren blushed and looked radiant, his eyes couldn't hide his excitement, "Thanks to Dr. Mu for your dislocation theory!"

As he spoke, Dong Xinren also felt grateful.

The dislocation theory has made theoretical achievements, but turning the theory into practice and handing over the project to the School of Mechanical Engineering is actually a debt of favor to the School of Materials and Mu Jingchi.

All over China, I don't know how many research teams can do this project of transforming theory into reality, but they fall in their School of Mechanical Engineering.

There are contacts here.

"To what extent?" Mu Jingchi didn't think about it so much, he paid more attention to the research results, and continued to ask.

"What we mainly do is the plastic deformation of metals, the plastic deformation of single crystals, polycrystals and alloys." When it comes to scientific research, Dong Xin also seriously reported to Mu Jingchi.

"Based on the dislocation theory, we have improved and controlled the plastic processing method more finely and accurately, and have been able to constrain the movement of some dislocations, thereby enhancing the mechanical properties of the material."

There are two ways of plastic deformation in single crystals: slip and twinning.The movement of dislocations causes slippage, thereby constraining the movement of dislocations and also changing and improving the properties of the material.

Most of the metals used in engineering are polycrystalline.Each grain in a polycrystal deforms in the same basic way as a single crystal.However, since the orientation of each grain in polycrystalline materials is different and there are many grain boundaries, the deformation is much more complicated.

In polycrystals, due to the irregular arrangement of atoms on the grain boundaries, the movement of dislocations is hindered, which increases the deformation resistance.The finer the metal grains, the more grain boundaries, the greater the deformation resistance, and the greater the strength of the metal.

When slip occurs, the soft dislocation grains start first, and when dislocations are hindered and gradually piled up at the grain boundaries, other grains slip.Confining dislocations and guiding dislocations will indirectly affect the grains.

When polycrystals are deformed, the grains are deformed in batches and steps, and the deformation is dispersed throughout the material.The finer the grain, the more dispersed the deformation of the metal, reducing the stress concentration, delaying the formation and development of cracks, and allowing the metal to undergo greater plastic deformation before fracture, thus improving the plasticity of the metal.

As for the plastic deformation of the alloy, it is divided into two categories.

When the constituent phase of the alloy is a solid solution, the solute atoms will cause lattice distortion, increase the slip resistance, and produce solid solution strengthening. The solute atoms are often distributed near the dislocation, which reduces the lattice distortion near the dislocation and makes the dislocation The ease of movement is reduced, the deformation resistance is increased, and the strength is increased.

When the structure of the alloy is composed of solid solution and dispersed metal compounds, the second phase silver particles become obstacles to the movement of dislocations.Under the action of external force, the dislocation line bends when it encounters the second phase particle, and after the dislocation passes through, a dislocation ring is left around the second phase particle.

The existence of the second phase hard point increases the resistance of dislocation movement, increases the slip resistance, and thus improves the strength of the alloy.

Of course, it's not as easy to do as it sounds.

"We found that this plastic processing method has universal applicability to metal materials, and the current effect is not obvious. According to our tests, it can only improve the mechanical properties by 20%."

"However, with future research, we are confident that we can achieve a 40% increase in mechanical properties."

The joy on Mu Jingchi's face naturally jumped up, and what Dong Renxin said was basically accurate.

"Thank you for your hard work."

In terms of material processing, Mu Jingchi doesn't know much about it. Now he is better at materials science, material physics and chemistry.

But he also knows how difficult it is to improve material properties through material processing, even with dislocation theory as a basis.This involves the yield and deformation resistance of metals, the thermodynamic conditions of metal plastic deformation, the change of metal plastic deformation and structural properties, the plasticity and fracture of metals, and plastic processing metallurgy.

There are also analysis and calculation methods involving the stress-strain state and stress-strain distribution in the deformed body, determining the physical and mechanical equations of deformed materials, and establishing deformation and force-energy parameters based on the basic equations of deformation mechanics and the characteristics of plastic processing and deformation processes, so as to provide correct selection. Plastic processing deformation methods, formulating reasonable process regulations, optimizing design tools, molds and processing equipment, analyzing and solving product defects provide basis for metal plastic processing mechanics.

"However, in terms of subsequent heat treatment, we don't have a good solution, and we can only process it according to the existing heat treatment process."

Dong Xinren looked at Mu Jingchi, with hope in his eyes, as if he desperately hoped that Mu Jingchi would give them another direction.

"For the time being, I can't do anything about heat treatment. I can only wait for the follow-up theoretical breakthrough. After the theoretical breakthrough, it should be able to guide the improvement of the heat treatment process."

Mu Jingchi shook his head, he didn't know when he would be able to break through the follow-up recovery and crystallized dislocation theory.

"Then let's continue digging deeper into plastic processing!" Dong Xinren said without much frustration on his face.

(End of this chapter)