The Unidirectional Growth of Copper–Indium Eutectoid Alloy

Abstract

Copper–indium eutectoid alloys have been unidirectionally transformed to produce pearlite that was aligned within ∼ 15° of the pulling direction. The relationship between unidirectional growth velocity V and interlamellar spacing λ was determined. At low growth velocities a growth law of Vλ^1·8±0·2 = constant existed that was consistent with the theoretical analyses for a volume diffusion controlled reaction. As the growth velocity increased, the exponent in the growth law continuously changed from 1·8 ± 0·2 to 3·35 ± 0·25. Kinetic factors were considered to be responsible for the exponent being greater than the value of 3 predicted for an interfacial diffusion-controlled reaction. A wide range of interlamellar spacings was found at each given growth velocity.