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Joining of ZrB 2 ‐Based Ultra‐High‐Temperature Ceramic Composites to Cu–Clad–Molybdenum for Advanced Aerospace Applications
Author(s) -
Singh Mrityunjay,
Asthana Rajiv
Publication year - 2009
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2008.02291.x
Subject(s) - materials science , composite material , ceramic , molybdenum , residual stress , thermal expansion , brazing , metallurgy , alloy
Three hot‐pressed ZrB 2 ‐based ultra‐high‐temperature ceramic composites (UHTCC), ZrB 2 –SiC p (ZS), ZrB 2 –SiC p –C (ZSC), and ZrB 2 –SCS9A (SiC fiber)–SiC p (ZSS), were joined to Cu–clad–Mo using AgCuTi brazes ( T L ∼1073–1173K) and Pd‐base brazes ( T L ∼1493–1513K). More extensive chemical interactions occurred in Pd‐base joints than in AgCuTi‐base joints. The Pd‐braze region displayed higher hardness in joints made using ZS than ZSS and ZSC. Residual stress calculations point toward negative strain energy up to ∼23% clad layer thickness because α Cu–clad–Mo <α ZS (α=coefficients of thermal expansion). Above this thickness, α Cu–clad–Mo >α ZS , strain energy is positive, and it increases with increasing thickness. Projected reductions in the thermal resistance highlight the benefits of joining the UHTCC to Cu–clad–Mo.