Study on the brazing process of titanium sound-reduction honeycomb core sandwich structure

Titanium sound-reduction honeycomb sandwich core structures were brazed by Ti-based brazing filler metals. Effects of brazing filler metal in different thickness on the blockage of sound-reduction holes, brazing interface defects, brazing interface microstructure and mechanical properties of honeycomb sandwich structures were comparatively investigated. Results shows that:with increasing of the thickness of brazing filler metal, the blockage ration of sound-reduction holes is improved, and the dissolution of brazing filler metal to honeycomb core foil is enhanced, which makes the tensile strength of honeycomb sandwich structure decreased dramatically. However, defects at brazing interface are significantly reduced along with the increase of the thickness of brazing filler metal. When the thickness of brazing filler metal is 30 μm at the brazing temperature of 920℃ with the holding time of 90 min, titanium sound-reduction honeycomb sandwich structure with good mechanical properties could be attained, and the experimental results are in good agreement with the theoretical results of the acoustic performance of titanium sound-reduction honeycomb sandwich structure.