Properties of scattered structures included in aluminum die castings.

Abstract

Practical aluminum die castings often include a number of scattered structures caused by destruction of solidified layers in a metal sleeve at a shot. The scattered structure-normal structure interface has tensile strength as low as 9 kg/mm2. The scattered structure lowers the strength of practical aluminum die castings and often causes defects of pressure leakage near the gate. The quantity of scattered structures are affected by solidification behaviors of molten metal in a metal sleeve at a shot. This quantity is estimated from the heat capacity of molten metal per unit area in the metal sleeve calculated by using die casting conditions.