E-Archive

VOL. 26 January ISSUE YEAR 2025

Interview

in Vol. 26 - January Issue - Year 2025
Application and Development of Laser Shock Peening
Dr. Hao Wang, Deputy director of Shanghai Engineering Research Center of Laser Intelligent Manufacturing

Dr. Hao Wang, Deputy director of Shanghai Engineering Research Center of Laser Intelligent Manufacturing

Plasma during laser shock peening

Plasma during laser shock peening

Laser shock peening on a blade

Laser shock peening on a blade

MFN had the opportunity to talk with Dr. Hao Wang, Deputy director of Shanghai Engineering Research Center of Laser Intelligent Manufacturing.

(?) MFN: What technical research does your team currently focus on?

(!) H. W.: At present, our team mainly focuses on the research and application of Laser Shock Peening, and we develop technical solutions and manufacture equipment for customers. Laser shock peening is not yet widely used for surface strengthening, but we are expecting a promising future for this very technique. Similar to the principle of mechanical shot peening commonly used in industry, laser shock peening uses high-energy pulsed lasers to generate ultra-high peak intensity shock waves on the surface of metallic materials, so that the microstructure of the metal surface at a certain depth is changed and compressive residual stress is generated on the top layer of metallic materials. The compressive residual stress is beneficial for the improvement of fatigue performance, wear resistance, and stress corrosion resistance of metallic materials. Laser shock peening technology has clear advantages as it is a non-contact cold processing process. It has broad application prospects in the aerospace field, especially in the surface strengthening treatment of components such as aircraft engine blades and blisks.

(?) MFN: What technical requirements do your customers have normally?

(!) H. W.: On the one hand, our customers need to ensure that the mechanical properties and compressive residual stress of parts after laser shock peening treatment meet their application requirements. On the other hand, our customers hope that we can improve the efficiency of laser shock peening processing and reduce the strengthening cost of individual parts. Although laser shock peening has obvious effects on improving the fatigue performance of aerospace parts, adaptions are also needed to balance between quality stability and cost control in the application of a large number of parts. Therefore, we have also made many technical changes during the laser shock peening process. It is also necessary to develop new optical systems to meet customer needs.

(?) MFN: What do you think of the future development of laser shock peening?

(!) H. W.: Laser shock peening has been applied to the aviation industry in the United States since the 1990s and its application scope is gradually expanding due to its excellent technical effects. In the future, the laser shock peening equipment should be a more convenient, more practical and easy to move strengthening system. However, this technology has been constrained by laser cost and processing efficiency. The processing cost for laser shock peening is much higher than that of traditional mechanical shot peening process. This also means that laser shock peening technology can be applied in more fields at a lower cost in the future if the laser technology could break through technical bottlenecks and cost barriers. As we all know, high-power fibre lasers were very expensive 10 years ago. With the development of industry technology, fibre lasers are now very cheap and have good technical parameters. Similarly, with the development of semiconductor-pumped solid-state laser technology, low-cost, high-pulse-energy and high-repetition-frequency nanosecond lasers suitable for laser shock peening will be bound to appear in the future, and laser shock peening technology will be used in more industrial part strengthening scenarios.

(?) MFN: What are the advantages of laser shock peening over traditional surface treatment techniques?

(!) H. W.: The advantages of laser shock peening are multifaceted. In terms of strengthening effect, laser shock peening can produce shock waves with a maximum intensity of tens of GPa within hundreds of nanoseconds, which is much higher than traditional mechanical strengthening. The strength and strain rate are extremely high, and the effect is mostly better than other surface strengthening processes. In terms of operability, laser shock peening technology is a non-contact process. The laser directly irradiates the absorption layer on the surface of the metallic materials without any contact, which effectively protects the surface integrity of the components. In terms of accuracy, the single-pulse laser of laser shock peening acts on the pre-set area in a very controllable manner, and the positioning accuracy can reach tens of microns, reducing the impact on the surrounding areas.

(?) MFN: In which field will laser shock peening be mainly used?

(!) H. W.: Laser shock peening is currently widely used in the aviation field, such as aircraft engine blades, blade disks, aircraft landing gear, and the connection between fighter jet fuselages and wings. This technology is also used in the energy field, such as gas turbine blade strengthening and nuclear power pressure vessel welds with laser shock peening as the post-treatment, to improve the fatigue life of key metallic materials, extend their service life, and reduce replacement or repair costs. Recently, with the widespread application of additive manufacturing technology, laser shock peening has opened up new application scenarios, such as using the shock waves induced by laser shock peening to regulate the microstructure and residual stress field distribution during the additive process, or using shock peening as a post-processing method for additive parts.

(?) MFN: What factors do you think should be paid more attention to in the future development of the laser shock peening?

(!) H. W.: We should meet customers’ technical needs, ensure their equipment quality to deliver perfect process service. At the same time, we should pay more attention to the overall industry development of this technology and establish in-depth cooperation with friendly companies and customers. On the one hand, we should ensure the continuous advancement of industry technology, and on the other hand, we should provide suitable solutions for customer needs. In addition, we should also focus on technology promotion because many people do not understand laser shock peening technology. We need to give more customers a deeper understanding of the potential application value of this technology.

(?) MFN: Is your team currently considering integrating AI with laser shock peening?

(!) H. W.: Our team has begun to apply AI technology to the development of laser shock peening processing and equipment, especially in control systems. With a large amount of experimental data obtained in the early stage of large-scale model training, we can plan reasonable and efficient laser shock peening technology paths for different materials, and implant them into our self-developed shock peening control systems to provide customers with more high-quality services. At the same time, we apply artificial intelligence to real-time monitoring of the laser shock peening process, to monitor the fluctuation of pulse energy and changes in shock wave intensity.

(?) MFN: How do you think companies that manufacture laser advanced manufacturing technology equipment can remain competitive?

(!) H. W.: To take the lead in the laser equipment industry, the team or company leader must determine the development direction in advance. One way is to expand the scale and broaden the market to maintain the leading position. Another way is to strengthen the subdivided field. We will focus on developing laser shock peening and discovering more applications in the industry.


MFN would like to thank Hao Wang for this interview!

For Information: 

Shanghai Laser Technology Research 

Institute Co., Ltd.

770 Yishan Road, Xuhui District

Shanghai, China

Tel. +86.15000671908

E-mail: siltwanghao@163.com

www.shlaser.com