【摘要】 本文用数值计算的方法对重力浇铸下功能梯度材料的凝固过程进行了数值模拟，分析了各种因素对颗粒分布的影响，并与实验结果进行了比较。结果表明，在形成的凝固体上部有一颗粒体积分数近于零的区域，而在靠近底部的区域内颗粒形成一种梯度分布．高的初始过热度或高的冷却温度将会使底部梯度区内颗粒体积分数略有增大，低的颗粒初始体积分数或小的颗粒尺寸会使底部梯度区范围增大，而梯度区内颗粒体积分数减小。更多还原

【Abstract】 A numerical investigation of solidification process during gravity casting of FGMs is conducted. The effects of various processing parameters were explored. The results are compared with experiment date. It is found that there exists a zone in the top portion of the solidification ingot where the particle volume fraction is nearly zero, and a graded region near the bottom. Higher superheat results in a higher particle concentration near the bottom, so do higher cooling temperatures. The lower initial particle volume fraction or small particle size leads to a thicker graded zone and a lower particle concentration near the bottom.更多还原