Study on Laser Surface Alloying of BT9 Titanium Alloy Carbon

8 under 9 Chin alloy carbon laser surface alloying research He Xiuli, Yu Ligen. Wang Huaming Department of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China Abstract: In order to improve the wear resistance of 619 titanium alloy, laser surface alloying was performed using carbon. The rapid solidification in-situ wear-resistant composite surface-synthesizing technology with a 1; as reinforcement phase is a very promising surface modification technology for improving the wear resistance of the titanium alloy.

1 Introduction Titanium alloys have the outstanding advantages of low density, high strength, excellent corrosion resistance, and good heat resistance. In the field of aero-engines, it is widely used as a key component for compressor disk compressor blades and fan blades, but titanium alloys have large friction coefficients.

Poor wear resistance seriously affects the performance of titanium alloys and limits their application in engineering. Solid nitriding ion nitriding plasma spraying and other technologies have been used to improve the wear resistance of titanium alloy 14, but the plasma nitriding and other technologies have the disadvantages of low abrasion resistance, thin wear-resisting layer, long processing cycle, difficult to control flexibly, and the like. Spraying is the presence of poor adhesion between the coating and the matrix and the laser surface modification of the material as a non-contact, non-polluting, high-efficiency, flexible color metal, 6 scoops, wear resistance, and corrosion resistance. Research. Has issued 6 papers. Contact Tel. 82,317,826 Fund Project National Natural Science Foundation 571050, Aviation Basic Science Foundation 950515 Fund 1. Project, alloying technology Surface modification of 1 intermetallic compound. A composite modified layer with a reinforcing phase was successfully produced on the surface. Due to the high hardness and wear resistance of the first-class ceramic compounds. This in-situ formed hard, strong phase can be firmly inlaid by the matrix and does not easily fall off during friction and wear.

Therefore, the surface modified layer has excellent wear resistance.

For this reason, the surface modification of 819 titanium alloy was performed using the carbon element laser surface alloying technology. A fast solidified in-situ wear-resistant composite material with high hardness 1 as the reinforcement phase was also successfully produced in the laser surface modified layer.

2 Test Method The surface of the small block sample 1247 is a laser treated surface. The surface alloying was performed using a sample coated with carbon powder on a continuous 0,2 laser facet. During the test, the axial flow is protected by argon gas, and the gas pressure is 0 35101 for the carbon element laser surface alloying test device. The carbon element or laser coating surface alloying parameter is the laser output material rate.

3 Test results and discussion 3.1 Microstructure analysis of laser alloyed surface modification layer of titanium alloy In the laser surface alloying process, the surface of the carbon powder is coated to blacken the sample surface, and the sample is added to the laser beam. Absorption rate; On the other hand, the carbon atoms in the carbon powder dissolve into the surface bath and alloy with the high-temperature alloy solution. The results of ray diffraction showed that after rapid solidification, a large number of dendritic and dendritic 1 structures were formed in the surface modification layer of 819 titanium alloy, 3 and a rapid solidification in-situ wear-resistant composite with hard 1 as the reinforcing phase was obtained. Material surface modified layer.

In the laser surface alloying structure of 819 titanium alloy laser surface alloyed 819 titanium alloy, the number and shape of one busy is strongly influenced by the laser process parameters. When the scanning speed is relatively low, the upper half of the alloyed layer exhibits a cyst-like structure, while the middle and middle-lower parts have a relatively dense dendrite structure. Due to the carbon powder coated on the sample surface, the sample is faced. The increase of the absorption rate of the laser increases the temperature gradient in the melting zone, which is not conducive to the formation of dendritic cells in the melting zone. When the scanning speed increases, the interaction time between the liquid metal and the carbon atoms in the molten pool becomes shorter, and the amount of carbon atoms dissolved into the laser molten pool decreases, so only a thin layer of dendritic first phase is generated on the upper part of the melting zone, and the volume occupied by the reinforcing phase is increased. The score also decreases by 3 and 31.

From 31, it can also be seen that there is no bonding interface between the laser surface alloyed modified layer of 819 titanium alloy and the matrix, which is a metallurgical combination of completely melting body. The microstructure has a gradual gradient from the bottom of the molten pool toward the free surface. The closer to the free surface, the higher the volume fraction in the organization.

This gradual change is determined by the laser surface alloying process and its rapid solidification process. When the molten pool metal solidifies, the solidification interface gradually advances from the bottom of the pool to the free surface. The closer the free surface is, the longer the interaction time between the alloy solution and the carbon powder is, the more carbon atoms are dissolved into the alloy solution, and the more the number 4 formed after rapid solidification, the more the laser surface alloying layer is modified on the 19 titanium alloy. The arborescent tissue also contains some black blocky phase. 4. The atomic fraction of the results of the energy spectrum analysis is. 77 004 people 1031 cubits, 87.59, but its high carbon content.

In fact, these black blocky phases are residual graphite particles that have not yet completely dissolved before they enter the bath. The number of particle morphology and the laser beam exposure time and laser beam energy density, that is, from the free surface distance laser power density laser beam scanning speed is determined. The influence of the presence of residual graphite particles on the tribological properties of the surface modification layer of Zheng 19 titanium alloy remains to be improved. Distance from the surface 19 titanium alloy laser surface alloyed surface modification layer Microhardness distribution Laser power 3.3 Scan speed 2683.2 Muscle 9 titanium Microhardness analysis of the alloy laser surface modified layer The microhardness distribution of the laser surface alloyed modified layer. The middle point is the alloying zone, the 8th zone is the heat affected zone, and the base is after 8 o'clock. It can be seen that after laser surface alloying of the 19-titanium alloy carbon element, the surface modification layer gradually decreases from high to low. This corresponds to the gradient of the microstructure in the modified laser surface layer. The farther away from the free surface, the smaller the volume fraction of 1 brother and therefore the lower the microhardness. In addition, the microhardness of the heat affected zone hardly increased.

4 Conclusions The laser surface alloying of Guang 9 titanium alloy was carried out by carbon element, and the surface modification layer of rapid solidification in-situ composite material with hard phase 1 as reinforcement phase was obtained; the laser surface modified layer was completely metallurgically combined with the substrate. The microstructure and hardness of the alloy have obvious gradient gradient characteristics. The carbon surface laser alloying technology is a promising surface modification technology to improve the wear resistance of the 89 titanium alloy.

Acknowledgments Professor Shen Guiqin from Beijing University of Aeronautics and Astronautics provided test materials. Thank you!

I3 Luo Jianjun, Wang Shihong, Shen Guiqin, Yu Youming. 6 Surface protection of 9 alloy fretting wear. Rare Metal Materials and Engineering, 19952445358.

5 Cao Hongyun. The status quo of laser surface treatment and its application in aerospace industry. Aerospace Materials Technology 199464851.

6 He Xiuli, Wang Huaming, Zheng Qiguang, Xu Desheng. Intermetallic compound carbon surface alloyed with laser. Metallurgy, 1998, 349983986.

Multi-punching Performance of Roller Chains Meng Fanzhong Wen Jianliang 21.Institute of Chain Drives, Jilin University of Technology, Changchun 130025, China; 2.Huzhou Huzhou Shuangshi Chain Transmission Co., Ltd., Huzhou 313012, Zhejiang, China The main wear mechanism of the chain is pin bushings. Crack propagation and exfoliation of the cylinder part. To ensure that the roller parts have sufficient strength and plasticity and use roll forming process is an effective method to improve the resistance of the roller parts.

In recent years, with the continuous innovation of mainframe products, the application of high-speed roller chains has become more and more extensive. Automotive engine timing chain and oil pump chain 06