金属型球铁磨球凝固时偏聚物和夹杂定位的研究

金属型球铁磨球凝固时存在非平衡异晶相。它不参与柱状晶成形,以自身晶相形态结晶,一部分被柱状晶偏聚到最后凝固区(LTF)的夹杂团块上。非平衡溶质La偏析在局部晶界上,而多数La汇集成夹杂团块。偏聚物和夹杂团块最后分布在柱状晶-等轴晶间的过渡区上。

Study on the Location of Segregated Solute and Inclusion of Ductile Iron Ball in the Metallic Mould during Solidification

There exists non-equilibrium abnormal crystal in nodular iron of metal mould during the solidification of grinding ball.It did not participate the formation of the column crystal in the non-equilibrium phase diagram but crystallized in the form of itself's phase shape when the temperature gradient is larger.Some portions of the non-equilibrium abnormal crystal segregated in the front of column crystal and collected together with inclusion.A small portion of non-equilibrium solute of rare-earth element Lanthanum segregated on local grain boundary during non-equilibrium solidification,whereas most of La coagulated into clumps of inclusion.Segregated solute and inclusion finally distributed at the transition region of the column crystal and the equiaxial grains.