Abstract
The results of studying the process of laser vacuum welding of elements of heat-shielding panels made of heat-resistant dispersion-strengthened powder materials Ni-20Cr-6Al-Ti-Y2O3 of increased strength are presented. Such materials can be used to create ultralight heat-shielding panels, which are systems integrated on the surface of aircraft from typical modules of a cellular structure.
 Technical solutions of heat-insulating modules are considered, which are a cellular (honeycomb) structure consisting of two plates with a thickness of 0.1 to 0.14 mm, inside which there is a thin honeycomb filler. It is shown that the small thickness of the plates and the complexity of integrating the elements into a single system significantly impair the formation of a strong connection of such elements and do not allow the direct use of the known methods of diffusion welding or vacuum brazing.
 It has been established that laser welding of elements of heat-shielding structures in vacuum provides satisfactory strength of the structure of the heat-shielding element as a whole. Local heating at certain points prevents deformation of the parts to be joined during the welding process. The use of a pulsed Nd:Yag laser with a power of 400–500 W, operating in the frequency range of 50–200 Hz, allows welding with or without a filler powder. It was found that the use of filler additives practically does not affect the mechanical properties of the welded joint, however, it reduces the melt zone, while increasing the density of the welded joint.
 Based on the results obtained, it was concluded that it is possible to use laser vacuum welding for the integration of thin elements of heat-shielding modules. It is shown that a satisfactory joint strength is achieved by ensuring high cleanliness of the surfaces of elements before welding, maintaining a high vacuum (less than 10–2 Pa) and rational thermal loading of the surfaces of the elements to be integrated.
 The use of the proposed process makes it possible to obtain a stronger and denser seam in comparison with the known methods of soldering multicomponent powder dispersion-strengthened materials
Highlights
Designs of heat-shielding panels for reusable spacecraft with an outer metal plate are being actively developed by leading experts from many countries [1, 2]
Today it is becoming evident that the most effective thermal protection consists of individual tile-modules attached to the hull of the spacecraft
Tiles can be integrated into a single system and separately from the body, with subsequent placement on surfaces requiring thermal protection
Summary
Designs of heat-shielding panels for reusable spacecraft with an outer metal plate are being actively developed by leading experts from many countries [1, 2]. Today it is becoming evident that the most effective thermal protection consists of individual tile-modules attached to the hull of the spacecraft. Tiles can be integrated into a single system and separately from the body, with subsequent placement on surfaces requiring thermal protection. Such integration requires welding or soldering of the plates simultaneously with the installation of a U-shaped elastic heat-compensating element, as well as additional fasteners (legs) that ensure fastening of the thermal protection to the surface of the spacecraft (Fig. 1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
