Chemically dealloyed Mg–Cu alloy lamina as an interlayer for reinforcing a C/C composite – TC4 alloy vacuum brazed joint

Abstract

Here, a novel brazing interlayer of bicontinuous nanoporous copper (NP–Cu) lamina was produced by chemically dealloying a magnesium-copper (Mg–Cu) binary alloy and applied for brazing a C/C composite and TC4 alloy along with AgCuTi alloy brazing filler. SEM, EDS, XRD, XPS, TEM and SAED were used to characterize the differences in microstructure and phase distribution of the samples and compare with samples without an interlayer. Mechanical testing in the form of shear tests were conducted to evaluate the change in shear strength caused by the interlayer. The large specific area, uniform nano scale porosity and ligaments of the NP-Cu lamina interlayer induced the transformation of Ti–Cu compounds from their bulk agglomerates to dispersed fine particles and formed eutectic phases, which contributed to relieving the residual stress and enhancing the plasticity of the joint seam. This led to a shear strength increase of 185% as compared to samples without an interlayer.