β-LiAlSiO4 reinforced Cu composite interlayer for brazing C/C composites and Nb

A novel type negative expansion beta-LiAlSiO4 (LAS) particles reinforced Cu composites was fabricated to reduce the generation of residual stress in C/C-Nb joints brazed with AgCuTi. LAS-Cu composite layer could disperse high-content LAS particles uniformly among brazing seam. It induced the gradient change of coefficient of thermal expansion (CTE) from C/C to Nb. High stress among brazing seam was weakened and C/C interface presented low stress condition. Cu matrix also maintains the activity of brazing alloy to form reliable bonding of C/C interface. The shear strength of joints modified with 40 vol% LAS-Cu interlayer was 40.9 +/- 2.8 MPa, which was 2.3 times more than that of original joints.