摘要
分别采用砂型和金属型浇注了1组高度相同直径不同的试棒,研究了试样由型壁至中心的二次枝晶间距的变化规律,分析了铸型冷却能力和试样尺寸造成的不同冷却速率对凝固组织的影响。结果表明,在砂型和金属型试样中,型壁至中心二次枝晶间距呈现依次增大的规律。随着试样直径增大,横截面上二次枝晶间距也增大,而且在砂型试样中二次枝晶间距随试样直径的增大更显著。得到了在砂型和金属型中平均二次枝晶间距λ与冷却速率v的关系为λ2=38.761 45 v-0.276 03。
Two groups of A357 alloy specimens with the same heights and different diameters were cast in sand and steel moulds. The variation of SDAS （second dendrite arm spacing） from the wall to the center in the cross section was studied, and the effects of the cooling rates caused by different moulds and sample diameters on the microstructures were analyzed. The results show that, in both sand and steel mould samples, SDAS increases from the wall to the eenter, and also increases with the increase of the sample diameter. Compared to the steel mould samples, the sand model samples have a more significant impact on the microstruetures. The relationship between SDAS h2 and cooling rates v is determined to be
出处
《铸造技术》
CAS
北大核心
2013年第4期393-396,共4页
Foundry Technology
基金
国家重点基础研究(973)资助项目(2011CB610403)
