【正文】
l growth of weld metal near fusion line. Such a growth initiation process, shown schematically in Figure , is called epitaxial growth or epitaxial nucleation. The arrow in each grain indicates its 100 direction. COMPETITIVE GROWTH IN BULK FUSION ZONE Figure Competitive growth in bulk fusion zone. Therefore, during solidification grains with their easygrowth direction essentially perpendicular to the pool boundary will grow more easily and crowd out those less favorably oriented grains, as shown schematically in Figure . This mechanism of petitive growth dominates the grain structure of the bulk weld metal.