過共晶アルミニウム—シリコン合金の初晶シリコンの微細化機構

抄録

  The change in the microstructure of hyper-eutectic Al-Si alloys containing silicon of 20%, which was made by adding phosphorous was studied by means of optical microscope, electron microscope and X-ray microanalyser. Fxperimental results were :
  1) Addition of phosphorous to hyper-eutectic Al-Si alloys resulted in remarkable refinement of primary silicon crystals.
  2) In the center of silicon crystal there existed a nucleus of grey color, having a shape similar to that of the silicon crystals.
  3) X-ray microanalyzer showed that the nucleus was a compound of Al-P.
  4) The effect of phosphorous addition made at 800°C was promoted by adding the other elements which had a tendency to retard the growth of primary silcon crystals.