かくはん微細化したアルミニウムの結晶粒径の分布ならびに結晶粒生成時期

抄録

  Correlation between grain forming characteristics and factors governing grain size was discussed from the viewpoint of grain distribution and the grain forming time estimated by a simple solidification model. The factors include molten metal stirring, Ti addition, cooling rate and purity of aluminum. New grain formation in high purity aluminum proceeds till the later stage of static solidification than that in low purity aluminum. Most of grains form both in low and high purity aluminum nearly at the same time in the early stage of solidification when they are stirred. Stirring has an opposite effect on aluminum containing 0.2%Ti. When the cooling rate is accelerated, a number of grains form, and the formation of new grains proceeds over the prolonged period throughout the solidification in aluminum being stirred or not.