Brazing of micrograin-filled quartz fiber reinforced silica composites and Invar using Ag-21Cu-4.5Ti alloy

摘要

Brazing of quartz fiber reinforced silica composites (QFSC) to Invar alloy was carried out in a vacuum at 1173 K for 10 min using Ag-21Cu-4.5Ti metal filler.Experiments indicated that composites prefilled with CaCO3 micrograins had good wettability.The CaCO3 decomposed to CaO during brazing.After brazing,a joint of structure QFSC/3CaO·2SiO2+Ti3O5+Fe2Ti+NiTi+Ag(s,s)+ Cu(s,s)/Invar was established.The shear strength of the brazed joint reached 11.6 MPa at room temperature,which is about five times the shear strength of that obtained without surface filling.