Development of multi-layered thermal protection system (TPS) for aerospace applications. (15th September 2015)

• Record Type: Journal Article
• Authors: Jayaseelan, D.D.; Xin, Y.; Vandeperre, L.; Brown, P.; Lee, W.E.
• Is Part Of: Composites. Volume 79(2015)
• Page Start: 392
• Page End: 405
• Publication Date: 2015-09-15
• Subjects: A. Ceramic-matrix composites (CMCs) -- Layers -- B. Interphase/interface -- D. Electron microscopy -- E. Joining -- E. Sintering; Composite materials -- Periodicals; Materials science -- Periodicals; Composite materials; Periodicals; Electronic journals; 620.118
• DOI: 10.1016/j.compositesb.2015.04.017
• Languages: English
• ISSNs: 1359-8368

Abstract

Abstract: Multi-layered UHTC composites for use in an extreme oxidation environment were fabricated by co-sintering. The multi-layered composite system consists of three layers and was designed with (i) an outer surface with the capacity to withstand heat fluxes in excess of 25 MW m −2, (ii) an intermediate layer with the ability to curtail diffusion of O2 and (iii) a bottom layer with better performance at high temperatures. One design has MeB2 (where Me = Zr or Hf) as the outer or top layer, MeC x O y as the intermediate layer and MeB2 /SiC as the bottom layer. Since little is known about MeC x O y ceramics, a detailed study has been carried out to synthesise and characterise them focussed on controlling MeC x O y stoichiometry. During co-sintering, the outer MeB2 layer thickness played a crucial role in providing a crack-free component. Indicative calculations of the residual stresses confirm that a compressive stress due to bending of the disks can stop crack growth through the MeB2 layer when its thickness is increased to 3 mm, and that the tensile stress in the bottom layer is also reduced. The cross-section microstructure of the optimised multi-layered UHTC composite shows a crack-free seamless interface.