【摘要】 富钇混合稀土对 ZL102合金的变质作用是肯定的,但受冷却速度的影响较大。一般说来,砂型铸造时变质效果较差,只有对壁厚小于5毫米的铸件才能获得良好的变质效果。富镧混合稀土与富钇混合稀土类似,对φ12的试棒,无论是显微组织还是机械性能都表明在砂型中变质效果较差。由于这一原因,稀土变质铝合金用于中小金属型铸件或具有金属型及砂芯的低压铸造较为合适。在这种情况下,稀土变质将优于钠变质。更多还原

【Abstract】 The effects of mischmetal rich in Y on the modification of ZL102 alloy has already been attested, but the magnitude of its effects is strongly influenced by the cooling rate. In general, the effect of the modification is weaker in the case of sand casting with the exception of the thin-section castings with the wall thickness of less than 5ram.This holds true for the mischmetal rich in La,which has been verified on the samples of φ12mm. through the observation on their microstruc- tures and the tests of their mechanical properties. For this reason,aluminum alloy castings of medium-and small-size appear to be more suitably modified in the ease of permanent-mould casting or low-pressure die casting with sand cores. In these cases, the modification using mischmetal rich in Y or La will show better results than that using sodium modifier.更多还原