Improving the joint strength of vacuum brazed Ti6Al4V alloy and SiO2(f)/SiO2 composites by Ti6Al4V and TiH2 powder modification of brazing filler alloys

Date

2025-1

Author

İnce, Burak Anıl

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This study aims to develop an appropriate brazing process for joining Ti6Al4V alloy and SiO2(f)/SiO2 composites, considering the components' characteristics and application requirements. Vacuum brazing was done using commercially available Incusil ABA and BAg-8 brazing filler alloys (in paste form) to maintain the process temperature below 900 ˚C. However, the wetting properties of these filler alloys on SiO2(f)/SiO2 composites are quite poor. Thus, to improve the joint strength these filler alloys were modified by adding different amounts of Ti6Al4V and TiH2 powders. To maintain the characteristics of the base material, the same heating and cooling profiles were used in all brazing experiments at temperatures between 750 and 850 ˚C with different holding times. Spreading areas of the filler alloys with varying powder concentrations were measured on the surfaces of the base materials. The hardness of the Ti6Al4V alloy was measured after brazing. Tensile tests on SiO2 fibers were conducted after heat treatments up to 800 °C, and compression test on SiO2(f)/SiO2 specimens were performed after each brazing processes. The strength of the joint was determined via the compressive shear tests. The maximum joint v strengths of about 16 MPa were obtained when 10 wt.% of the powder combination was added at a holding temperature of 800 ˚C and held for 15 and 30 minutes for Incusil ABA and BAg-8 filler alloys, respectively. The results of the mechanical tests were evaluated based on the microstructural examinations of the joint interfaces via SEM and EDS analysis.

Subject Keywords

Ti6Al4V, SiO2(f)/SiO2 composites, Vacuum Brazing, Filler alloys, Joint strength

URI

https://hdl.handle.net/11511/113540

Collections

Graduate School of Natural and Applied Sciences, Thesis