No abstract

Microstructure evolutions and degradations of aluminum-metal-matrix composites during fusion welding were studied and compared with thermodynamic calculations. In fusion welds of Al 2 O 3 -reinforced composites, the decomposition of Al 2 O 3 was observed. In fusion welds of SiC whisker-reinforced composites, the decomposition of SiC to Al 4 C 3 ϩ Si by reaction with molten aluminum occurred. These phenomena led to unacceptable fusion welds in aluminum metal-matrix composites. Successful welds were produced in the same composites by friction stir welding (FSW). Significant reorientation of SiC whiskers close to the boundary of the dynamically recrystallized and thermomechanically affected zone (TMAZ) was observed. The small hardening in the dynamically recrystallized region was attributed to the presence of dislocation tangles in between SiC whiskers.

No abstract

No abstract

Fabrication of defect free co-sintered electrolytes with thickness between 12 μm and 40μm has been demonstrated on planar and tubular cells produced via a spray coating process. Leak testing using a helium leak method showed low diffusional leak rates for cells using optimized spray parameters. The electrolytes were characterized using scanning electron microscopy to qualitatively assess pin holes. Average open circuit voltages (OCVs) of 1080 mV were obtained on tubular cells with spray-coated electrolytes using 3% humidified hydrogen as the fuel. This paper presents spray coating as a viable, cost effective method for electrolyte application in co-fired, anode supported SOFCs.