Silicon eutectic alloy composition and method of making by rotational casting

The method of 2, wherein an outer surface of the mold is cooled at a rate of at least about 100 degrees Celsius (° C.) per minute, a wall of the mold separating the outer surface from the inner surface.

A silicon eutectic alloy composition comprising:

• a body comprising a eutectic alloy including silicon, one or more metallic elements M, and a eutectic aggregation of a first phase comprising the silicon and a second phase of formula MSi2, the second phase being a disilicide phase,
• wherein one of the first and second phases of the eutectic aggregation comprises one or more colonies of substantially aligned high aspect ratio structures;
• wherein the body comprises a fracture toughness of at least about 3.2 megaPascals·meter1/2(MPa·m1/2).

A silicon eutectic alloy composition comprising:

• a body having symmetry about a longitudinal axis thereof, the body comprising a eutectic alloy including silicon, one or more metallic elements M, and a eutectic aggregation of a first phase comprising the silicon and a second phase of formula MSi2, the second phase being a disilicide phase,
• wherein one of the first and second phases of the eutectic aggregation comprises high aspect ratio structures oriented along a radial direction with respect to the longitudinal axis.