FRICTION STIR WELDING OF OXIDE DISPERSION STRENGTHENED ALLOY MA956

摘要

Ferritic oxide dispersion strengthened MA956 alloys (ODS) were joined using friction stir welding (FSW) as a means of joining these alloys without disturbing the dispersion characteristics. Two MA956 plates of thickness 12.7 mm and 6.4 mm were successfully plasticized by friction stir welding (FSW). Fully consolidated welds were made at 400 RPM (50 mm/min) with Q60 composite pin tools and 600 RPM (13 mm/min) with W-Re pin tool. Post weld heat treatment was performed at 1000℃ and 1300℃ to observe the effects of heat treatment on the weld properties. Microstructural characterization, grain size analysis, and mechanical property measurements were performed as a function of weld processing parameters. Microhardness in the weld region showed a modest reduction in the strength compared to the as-processed MA956. The oxide dispersion between the bulk and the weld was analyzed by small angle neutron scattering (SANS) and scanning electron microscope (SEM).